# List of Octonauts episodes

This is a list of episodes of the television series Octonauts, which is a British children's television series, produced by Silvergate Media for the BBC channel CBeebies.

## Series overview

| Series | Episodes | Episodes | Originally released | Originally released |
| Series | Episodes | Episodes | First released | Last released |
| 1 | 50 | 50 | 4 October 2010 (2010-10-04) | 11 February 2011 (2011-02-11) |
| 2 | 22 | 22 | 19 November 2012 (2012-11-19) | 3 September 2013 (2013-09-03) |
| 3 | 20 | 20 | 4 September 2013 (2013-09-04) | 22 September 2015 (2015-09-22) |
| 4 | 24 | 24 | 23 September 2015 (2015-09-23) | 27 October 2017 (2017-10-27) |
| Specials | 12 | 12 | 13 December 2010 (2010-12-13) | 30 March 2021 (2021-03-30) |
| 5 | 27 | 27 | 27 March 2023 (2023-03-27) | present |

## Episodes
### Series 1 (2010–2011)

Written by: Stephanie Simpson, Billy Aronson, Glen Berger, Ian Carney, Cydne Clark, Cusi Cram, Sarah Durkee, Steve Granat, Carin Greenberg, Jonathan Greenberg, Peter K. Hirsch, Adam Idelson, Dave Ingham, Catherine Lieuwen, Myles McLeod, Allan Neuwirth, Sascha Paladino, and Gabe Pulliam.
| No. overall | No. in series | Title | Octo-Alert sounded by | Original release date | Creature Report original air date |
| 1 | 1 | "Octonauts and the Whale Shark" | Peso | 4 October 2010 | 9 January 2011 |
| When Dashi is swallowed by a whale shark, mistaken for a cave, the Octonauts venture inside of him to come and rescue her. ||||||
| 2 | 2 | "Octonauts and the Undersea Storm" | Dashi | 5 October 2010 | 15 January 2011 |
| An undersea storm is approaching so Kwazii helps some creatures on a coral reef reach safety, but then he crashes the Gup-B while he is also trying to race back to the Octopod. When the GUP-C's tow-rope snaps while rescuing him, some reef lobsters Kwazii helped earlier lend a hand by holding the broken rope ends together with their strong claws. ||||||
| 3 | 3 | "Octonauts and the Crab and Urchin" | Kwazii | 6 October 2010 | 6 February 2011 |
| Barnacles and Kwazii investigate a disruption on a nearby reef; A carrier crab and the urchin he keeps on top of his shell as a defence against predators has a falling out and just can't seem to get along. ||||||
| 4 | 4 | "Octonauts and the Walrus Chief" | Barnacles Kwazii | 7 October 2010 | 1 February 2013 |
| A walrus mistakes Peso's medical bag for a clam and takes it home. Walruses don't like other animals near their colonies, so Captain Barnacles, Kwazii, and Peso disguise themselves as a fellow walrus to sneak into the dangerous colony and retrieve the medical bag. ||||||
| 5 | 5 | "Octonauts and the Flying Fish" | Kwazii | 8 October 2010 | 14 May 2011 |
| A school of flying fish accidentally make off with Professor Inkling's rare book and the Octonauts rig up the GUP-B to get it back. ||||||
| 6 | 6 | "Octonauts and the Giant Squid" | Inkling | 11 October 2010 | 23 January 2011 |
| The Octonauts set out to find and photograph Inkling's long-lost cousin, the giant squid. ||||||
| 7 | 7 | "Octonauts and the Orcas" | Kwazii Barnacles (briefly) | 12 October 2010 | 5 February 2011 |
| An enormous killer whale is stranded on a beach, and with some help from some fiddler crabs, the Octonauts manage to rescue him. ||||||
| 8 | 8 | "Octonauts and the Great Algae Escape" | Barnacles | 13 October 2010 | 17 April 2011 |
| The crew must catch a runaway Octopod after it is hijacked by a group of crustaceans who are trying to flee an area of seabed being polluted with algae by a broken pipeline. ||||||
| 9 | 9 | "Octonauts and the Remipedes" | Tweak | 14 October 2010 | 12 February 2011 |
| Shellington goes to search for a group of remipedes in a cave but he hasn't driven the GUP-D before and ends up crashing it and breaking it. The other Octonauts try to save him but they get lost too. Luckily, a group of blind remipedes help them find their way out of the cave. ||||||
| 10 | 10 | "Octonauts and the Speedy Sailfish" | Barnacles | 15 October 2010 | 21 May 2011 |
| Tweak's remote control system for the Gups' malfunctions, so Barnacles and Kwazii are forced to chase after them with the pedal-driven GUP-F. Luckily some speedy sailfish, the fastest fish in the sea, are persuaded to show their off prowess by rounding up the speeding Gups. ||||||
| 11 | 11 | "Octonauts and the Blobfish Brothers" | Dashi | 18 October 2010 | 7 May 2011 |
| The Octonauts must evacuate some slow-moving, gelatinous blobfish before an undersea volcano erupts. ||||||
| 12 | 12 | "Octonauts and the Monster Map" | Kwazii | 19 October 2010 | 16 January 2011 |
| Kwazii has a pirate map showing the location of a sunken treasure ship that allegedly harbours a Kraken-like a sea monster, but it turns out to be an octopus that can change colour to camouflage himself. ||||||
| 13 | 13 | "Octonauts and the Lost Sea Star" | Kwazii | 20 October 2010 | 28 May 2011 |
| A sea star (starfish) named Twinkle has got lost on the beach, but the Octonauts have to search the sea from top to bottom to find her home, as there are nearly 2000 species of sea star living at all levels of the ocean. On a reef in the Sunlight Zone, they encounter a sunflower seastar and a predatory porcupine pufferfish. In the Twilight Zone they encounter brittle stars and get chased into a cave by a wolf eel, where they notice Twinkle glows in the dark, which means she is from the Midnight Zone. They end up crashing the Gup at the bottom of an ocean trench, but luminous sea stars light the way out for them. ||||||
| 14 | 14 | "Octonauts and the Albino Humpback Whale" | Kwazii | 21 October 2010 | 22 January 2011 |
| The Octonauts think they've seen a ghost but it turns out to be an albino humpback whale who is moaning from the pain of a nasty sunburn. ||||||
| 15 | 15 | "Octonauts and the Giant Kelp Forest" | Tweak | 22 October 2010 | 10 April 2011 |
| Kwazii's favorite sub, the GUP-B, goes missing in a huge kelp forest due to Kwazii pressing the eject button while the engine was active (Something Tweak advised him not to do) and Kwazii, Captain Barnacles, and Shellington must retrieve it, meeting strange and interesting creatures along the way. ||||||
| 16 | 16 | "Octonauts and the Enemy Anemones" | Pudding (Accidentally) | 25 October 2010 | 22 May 2011 |
| The Octonauts land on an island for a picnic, but first, must help some crabs trapped between two warring groups of aggregate anemones. Meanwhile, back on the Octopod, a horde of out-of-control puddings come to attack. ||||||
| 17 | 17 | "Octonauts and the Narwhal" | Dashi | 26 October 2010 | 23 April 2011 |
| When the Octopod cruises underwater to Captain Barnacles' homeland, the North Pole, it gets trapped in the Arctic sea ice, but one of Barnacles' old friends, Boris the narwhal, helps them break through the ice with his long tusk. ||||||
| 18 | 18 | "Octonauts and the Midnight Zone" | Tweak | 27 October 2010 | 15 May 2011 |
| The Octonauts explore the deepest part of the ocean where no daylight ever reaches and find some hydrothermal vents where vent fish, limpets and tube worms live, and they also discover a new species of worm to be put in Shellington's book. ||||||
| 19 | 19 | "Octonauts and the Snapping Shrimp" | Peso | 28 October 2010 | 24 April 2011 |
| A little shrimp with a big claw makes such a loud noise that it stuns the Octonauts. A video of it made by Dashi reveals that the sound and accompanying shock wave are caused by the shrimp while she was making a cavitation bubble with her claw. ||||||
| 20 | 20 | "Octonauts and the Snot Sea Cucumber" | Kwazii | 29 October 2010 | 30 January 2011 |
| After an underwater tremor, an injured sea cucumber named Slippy gets loose on the Octopod, so to let her breathe, they flood the ship! ||||||
| 21 | 21 | "Octonauts and the Giant Whirlpool" | Tweak | 1 November 2010 | 8 May 2011 |
| The Octonauts race against time to rescue Tweak's friend, a leatherback sea turtle named Sandy when she is swept away in a current (leading to a whirlpool) from the Australian coast where she was preparing to lay her eggs. ||||||
| 22 | 22 | "Octonauts and the Hermit Crabs" | Tweak | 2 November 2010 | 16 April 2011 |
| With half the crew stranded in a rock pool due to a low tide, Peso and Tweak help to remove a stuck hermit crab from the shell he has outgrown. ||||||
| 23 | 23 | "Octonauts and the Mixed Up Whales" | Barnacles | 3 November 2010 | 9 April 2011 |
| The Octonauts clean and repair the Octopod, but the loud noises they are creating confuse the sonar of two blue whales who are looking for each other so much that they almost crash into the ship. ||||||
| 24 | 24 | "Octonauts and the Kelp Forest Rescue" | TBA | 4 November 2010 | TBA |
| Peso's little brother Pinto visits the Octonauts and gets an eyepatch from Kwazii. He becomes more interested in being a pirate than a medic (stating that he wanted to be a 'real' Octonaut like Kwazii). But when he helps Barnacles, Kwazii, and Peso in a mission to help Dashi and Shellington escape, he begins to like being a medic. This is the only episode where the Octo-Alert was sounded by itself, where no one was filmed pressing any of its buttons until a later episode in the fourth season. ||||||
| 25 | 25 | "Octonauts and the Decorator Crab" | Kwazii | 5 November 2010 | 8 January 2011 |
| The Octonauts stake out a thief, who turns out to be a decorator crab, stealing their things to decorate his shell. ||||||
| 26 | 26 | "Octonauts and the Beluga Whales" | Kwazii | 6 December 2010 | 29 May 2011 |
| The Octonauts lead a pod of beluga whales stuck under the pack ice to safety by getting them to follow Peso while he's playing the same tune as the beluga's song on his xylophone. ||||||
| 27 | 27 | "Octonauts and the Hungry Pilot Fish" | Peso | 7 December 2010 | 4 June 2011 |
| The Octonauts are chased by a whitetip shark only to discover all he needed was a pilot fish to clean his teeth, and he just so happens that they have just met a lonely pilot fish that is hungry for action. ||||||
| 28 | 28 | "Octonauts and the Vampire Squid" | Kwazii | 8 December 2010 | 5 June 2011 |
| When Peso goes on a solo training dive to the Midnight Zone, he encounters a hurt vampire squid. When he's scared by the sudden arrival of Kwazii and Captain Barnacles, he sprays them with sticky bioluminescent mucus and flees, but in the end, Peso can help him out. ||||||
| 29 | 29 | "Octonauts and the Seahorse Tale" | Peso | 9 December 2010 | 13 April 2013 |
| After a storm, the Octonauts help a female seahorse search for her missing mate. She tells them to Kwazii's surprise that the missing male seahorse is about to give birth to baby seahorses! ||||||
| 30 | 30 | "Octonauts and the Giant Jelly" | Barnacles | 10 December 2010 | 5 January 2013 |
| The Octonauts must rescue Peso when he gets trapped inside a giant ctenophore. ||||||
| 31 | 31 | "Octonauts and the Cookiecutter Sharks" | Tweak | 13 December 2010 | 11 June 2011 |
| Some mysterious holes that keep appearing in the Octonauts' equipment turn out to be the work of cookiecutter sharks whose bioluminescence initially made them invisible against the light coming down from the sea surface. ||||||
| 32 | 32 | "Octonauts and the Oarfish" | Pinto | 14 December 2010 | 12 June 2011 |
| Dashi catches a glimpse of an elusive creature that appears to be a giant sea serpent and manages to photograph his tail. The truth is stranger than fiction when he appears to be an awesomely, long oarfish. ||||||
| 33 | 33 | "Octonauts and the Combtooth Blenny" | Dashi | 15 December 2010 | 18 June 2011 |
| Kwazii crashes the GUP-E, leaving him and Peso marooned on a desert island inhabited by a fish who can walk on land. Their SOS message to the Octonauts is relayed in increasingly garbled form via the blenny, a blue fish a squid, and an angler fish. ||||||
| 34 | 34 | "Octonauts and the Jellyfish Bloom" | Kwazii | 16 December 2010 | 19 June 2011 |
| Shellington gets trapped by sea nettle jellyfish whilst observing garden eels in the GUP-E. Barnacles, Kwazii, and Peso attempt to save him but Barnacles gets stung by a jellyfish. Luckily, Peso heals it using vinegar and then goes to save Shellington along with Kwazii. ||||||
| 35 | 35 | "Octonauts and the Baby Dolphin" | Tweak | 17 December 2010 | 25 June 2011 |
| A young dolphin follows Kwazii home while he's babysitting him and the Octonauts must search for his mummy. ||||||
| 36 | 36 | "Octonauts and the Scary Spookfish" | Dashi | 24 January 2011 | 26 June 2011 |
| Peso gets jammed in an ocean trench when the GUP-E's battery dies and is surprised by a strange deep sea fish with a transparent head: a Spookfish called Boo, whose ability to see vertically comes in handy as GUP-C winches GUP-E back up the narrow trench. ||||||
| 37 | 37 | "Octonauts and the Arctic Orcas" | Kwazii | 25 January 2011 | 3 April 2011 |
| Captain Barnacles and Peso get lost in the icy Arctic sea when the GUP-E gets stuck in an iceberg and the Gup finder is damaged. Fortunately, a pod of orcas help Kwazii find them. ||||||
| 38 | 38 | "Octonauts and the Slime Eels" | Kwazii | 26 January 2011 | 2 April 2011 |
| In the North Atlantic, Kwazii searches the sunken shipwreck of his pirate grandfather, Calico Jack, for his gold spyglass. It's guarded by blind hagfish (slime eels), but their slime unexpectedly helps him when he gets stuck. Kwazii ends up leaving the spyglass because it's now the home of sea creatures. ||||||
| 39 | 39 | "Octonauts and the Enormous Elephant Seal" | Kwazii | 27 January 2011 | 27 March 2011 |
| An enormous elephant seal is brought into the Octopod to moult as moulting underwater is dangerous. But then he overstays his welcome in the Octopod. ||||||
| 40 | 40 | "Octonauts and the Sardine School" | Dashi | 28 January 2011 | 26 March 2011 |
| The Octonauts must work together as a team to help a lost sardine find her school. ||||||
| 41 | 41 | "Octonauts and the Dolphin Reef Rescue" | Barnacles | 31 January 2011 | 20 March 2011 |
| Peso and the gang try to repair a reef by replacing bleached corals, but a pod of playful dolphins make mischief for them until they discover that helping can be fun too. ||||||
| 42 | 42 | "Octonauts and the Eel Ordeal" | Dashi | 1 February 2011 | 19 March 2011 |
| In a rare journey into fresh waters (a river), the Octonauts follow some migrating eels and help an injured eel on his difficult journey when he gets stranded from the others. ||||||
| 43 | 43 | "Octonauts and the Marine Iguanas" | Dashi Kwazii | 2 February 2011 | 13 March 2011 |
| The team are preparing for a feast of red seaweed on the Galápagos Islands but a trio of salt-sneezing marine iguanas raid the Octopod and eat it all! ||||||
| 44 | 44 | "Octonauts and the Dwarf Lanternshark" | Barnacles | 3 February 2011 | 12 March 2011 |
| Down in the darkness of the ocean deep, Peso and the Octonauts must help a tiny, injured dwarf lantern shark. But they have to find him first since he's so small! ||||||
| 45 | 45 | "Octonauts and the Pirate Parrotfish" | Kwazii | 4 February 2011 | TBA |
| Kwazii discovers Calico Jack's Parrot Island treasure map behind an old photo. While looking for the island they meet a parrotfish, who helps them clear away dense algae and hide from vicious moray eels. ||||||
| 46 | 46 | "Octonauts and the Electric Torpedo Rays" | Tweak (failed) Vegimals (chirped) | 7 February 2011 | 5 March 2011 |
| Some electric torpedo rays give the Octopod a jump-start when its batteries go flat during a trip to see Tweak's pal, Sandy the leatherback sea turtle. ||||||
| 47 | 47 | "Octonauts and the Crafty Cuttlefish" | Barnacles (Demonstration) Tunip | 8 February 2011 | 27 February 2011 |
| Captain Barnacles allows Tunip to use his Octo-compass. But when Tunip loses it, a cuttlefish takes it. ||||||
| 48 | 48 | "Octonauts and the Lost Lemon Shark" | Peso | 9 February 2011 | 26 February 2011 |
| The Octonauts look after a young lemon shark named Lemmy who has hurt his nose and can't find his way home. ||||||
| 49 | 49 | "Octonauts and the Humuhumunukunukuapua'a" | Dashi | 10 February 2011 | 20 February 2011 |
| The Octopod's waterworks become clogged with frightened reef triggerfish. The Octonauts must find a way to flush them out. ||||||
| 50 | 50 | "Octonauts and the Giant Spider Crab" | Barnacles | 11 February 2011 | 19 February 2011 |
| The Octonauts help a 100-year-old spider crab that has got his leg trapped in a giant clam whilst en route to his 100th birthday party. It turns out that Kwazii's afraid of spiders, but he still helps, even though he thought the spider crab was a real spider at first. ||||||

### Series 2 (2012–2013)

A second series of 22 episodes started on 19 November 2012 on the UK's CBeebies channel, but was halted with no explanation after 10 episodes, leading to criticism from viewers. Broadcasts resumed in March 2013, but stopped a week later (with the last 7 episodes still unaired). 5 of the remaining episodes were released in May 2013 and then the last 2 episodes were released in September 2013, just before the broadcast of series 3.
Written by: Ken Pontac, Rich Fogel, Jimmy Hibbert, Dean Stefan, Adam Peltzman, Billy Aronson, Danny Stack, Cydne Clark, Carin Greenberg, Allan Neuwirth, Nicky Phelan, Raye Lankford, Gabe Pulliam, Adam Idelson, Sam Dransfield, Davey Moore, and Steve Clark
| No. overall | No. in series | Title | Octo-Alert sounded by | Original release date | Creature Report original air date |
| 51 | 1 | "Octonauts and the Colossal Squid" | Dashi | 30 September 2015 | 19 November 2012 |
| The Octopod is attacked by a colossal squid, which drags the ship down an abyssal trench, forcing Barnacles and Kwazii to make a perilous swim outside to confront the gigantic beast. ||||||
| 52 | 2 | "Octonauts and the Adelie Penguins" | Dashi | 22 September 2015 | 20 November 2012 |
| While Kwazii and Peso have their hands full babysitting a bunch of Adelie penguin chicks, Captain Barnacles must rescue the chicks' parents from a perilous sea storm! ||||||
| 53 | 3 | "Octonauts and the Coconut Crabs" | Kwazii | 29 September 2015 | 21 November 2012 |
| Kwazii finds a mysterious, unbreakable coconut, so the Octonauts seek out the help of some large, island-dwelling coconut crabs to open it. ||||||
| 54 | 4 | "Octonauts and the Great White Shark" | Peso | 28 September 2015 | 22 November 2012 |
| Peso must perform an emergency fin bandage on a hungry great white shark, but first they need to subdue the giant predator using a trick called 'tonic immobility'. ||||||
| 55 | 5 | "Octonauts and the Sea Snakes" | Peso | 24 September 2015 | 23 November 2012 |
| It's sea snakes on the Octopod when a poisonous sea krait lays her eggs in the garden pod, just as Captain Barnacles has to navigate the ship past a treacherous whirlpool. ||||||
| 56 | 6 | "Octonauts and the Bowhead Whales" | Dashi | 30 September 2016 | 26 November 2012 |
| Captain Barnacles' narwhal friends (see Series 1, episode 17) are trapped under the Arctic ice. After failing to rescue them with the GUP-C's icebreaker and the GUP-D's drill, they enlist the help of some bowhead whales whose massive heads can break through thick ice. ||||||
| 57 | 7 | "Octonauts and the Jawfish" | Barnacles | 16 November 2015 | 27 November 2012 |
| A jawfish father has lost the eggs he was brooding and the Octonauts must bring them safely back to him! ||||||
| 58 | 8 | "Octonauts and the Porcupine Puffer" | Peso | 17 November 2015 | 28 November 2012 |
| The Octonauts venture inside a whale shark again (see Series 1, episode 1), this time they need to rescue a porcupine puffer fish named Puffy before it's too late! ||||||
| 59 | 9 | "Octonauts and the Damselfish" | Barnacles | 2 October 2015 | 29 November 2012 |
| Some algae-eating fish need help dealing with damselfish that chase them off the algae they are farming. ||||||
| 60 | 10 | "Octonauts and the Scared Sperm Whale" | Barnacles | 18 November 2015 | 30 November 2012 |
| Peso tries to help a young timid sperm whale named Simon to overcome his fear of deep diving, an ability Captain Barnacles and Kwazii must use their brains later to rescue Peso when he gets caught by a giant clam on the seabed. ||||||
| 61 | 11 | "Octonauts and the Long-armed Squid" | Peso | 19 November 2015 | 11 March 2013 |
| Peso and Kwazii search a creepy shipwreck in the midnight zone, looking for an injured creature that their friend the vampire squid (see Series 1, episode 28) has heard moaning in the dark. Peso soon finds an injured angler fish but the real source of the moaning turns out to be a long-armed squid, a strange ghostly white creature with elbows in his extraordinarily long tentacles, one of which has become trapped in the timbers of the wreck. ||||||
| 62 | 12 | "Octonauts and the Fiddler Crabs" | Barnacles | 20 November 2015 | 12 March 2013 |
| The Octopod's periscope breaks off during a storm and lands up on a beach, lost amongst other marine debris. The Octonauts clean up the beach whilst searching for the periscope but a resident colony of fiddler crabs mistake the GUP-D and its claw gestures for a hostile giant crab and attack. The GUP-D goes haywire with a fiddler crab at the controls and burrows under the beach causing a sinkhole to appear which almost swallows them all up. In the end, the crabs fill the hole with the sand balls they regurgitate whilst feeding. ||||||
| 63 | 13 | "Octonauts and the Manta Rays" | Dashi | TBA | 13 March 2013 |
| A young manta ray named Mirelle needs help finding the secret manta ray feeding grounds. But when she and the Octonauts finally locate it, they find themselves caught in the middle of a feeding frenzy! ||||||
| 64 | 14 | "Octonauts and the Swashbuckling Swordfish" "Octonauts and the Flying Swords" (US title) | Dashi | TBA | 14 March 2013 |
| When Kwazii sees what seem to be three flying swords under the Pirate's Moon, he embarks on a quest to find the Sword of the Pirate King, which legend says is on a wreck guarded by magical flying swords. The three "flying swords" turn out to have been three swordfish, which love jumping out of the water, but the pirate sword proves to be real. Meanwhile, the others are led on a wild goose chase into a kelp forest following the pirate wreck's drifting figurehead, a carving of a pirate cat, which they mistake for Kwazii. ||||||
| 65 | 15 | "Octonauts and the Triggerfish" | Barnacles | TBA | 15 March 2013 |
| The Octonauts' floating temperature sensors alert them to a risk of waterspouts due to a rise in sea surface temperature so they decide to retrieve the devices for safe-keeping. But Kwazii gets into an argument with a possessive triggerfish named Trixie which has adopted one of the devices as its home, and they both get carried away by a waterspout. Kwazii ends up having to defend the fish from a seabird and a swordfish who want to eat her. Luckily the characteristic grunting sounds that triggerfish make when distressed enables the other Octonauts to locate them. ||||||
| 66 | 16 | "Octonauts and the Mimic Octopus" | Kwazii | TBA | 13 May 2013 |
| Peso is gathering red algae to cure the sick vegimals but needs the shapeshifting skills of a mimic octopus named Mortamor to scare off a moray eel by using its striped tentacles to pretend to be a group of poisonous sea snakes! ||||||
| 67 | 17 | "Octonauts and the Lionfish" | Peso | TBA | 14 May 2013 |
| Invasive lionfish are damaging coral reefs in the Atlantic Ocean and need taking back to their native Pacific Ocean so the Octonauts must use the Octopod to transport them to their native habitat. ||||||
| 68 | 18 | "Octonauts and the Leafy Sea Dragons" | Kwazii | TBA | 15 May 2013 |
| When some leafy sea dragons accidentally get into the Octopod, the Octonauts must find them before they end up in Kwazii's stew! ||||||
| 69 | 19 | "Octonauts and the Manatees" | Barnacles | TBA | 16 May 2013 |
| After his Gup is struck by lightning, Captain Barnacles gets trapped by a giant clam but doesn't call for help as he wants the others to go help some manatees at risk from a thunderstorm. ||||||
| 70 | 20 | "Octonauts and the Saltwater Crocodile" | Dashi | TBA | 17 May 2013 |
| An enormous Australian saltwater crocodile is lost in the Antarctic Ocean and the Octonauts must bring him home without anyone getting hurt. ||||||
| 71 | 21 | "Octonauts and the Humphead Parrotfish" | Dashi | TBA | 2 September 2013 |
| The Octonauts use magnets and a rock-chomping humphead parrotfish named Hatty to try to stop a large meteor that's heading towards the Octopod. ||||||
| 72 | 22 | "Octonauts and the Gulper Eels" | Dashi | TBA | 3 September 2013 |
| Hungry gulper eel brothers as well as undersea tremors threaten Inkling and Kwazii and get trapped by boulders. So Dashi uses Tweak's newly built "Octo Mach-Suit" to rescue them. ||||||

### Series 3 (2013–2014)

A third series of 20 episodes started being broadcast by CBeebies on 4 September 2013.
Written by: Gabe Pulliam, Carin Greenberg, Adam Idelson, Adam Peltzman, Allan Neuwirth, Billy Aronson, Danny Stack, Davey Moore, Dean Stefan, Jimmy Hibbert, Ken Pontac, Nicky Phelan, Raye Lankford, Rich Fogel, Samuel Dransfield, Steve Clark, and Cydne Clark
| No. overall | No. in series | Title | Octo-Alert sounded by | Original release date |
| 73 | 1 | "Octonauts and the Siphonophore" | Kwazii Dashi | 4 September 2013 |
| Kwazii and Dashi become entangled in a strange deep-sea creature - a siphonophore - and when a geyser blasts it toward the surface, the Octonauts must stop its ascent before it fatally bursts. |||||
| 74 | 2 | "Octonauts and the Water Bears" | Barnacles | 5 September 2013 |
| The Octonauts venture into a dangerous red-hot lava tube to rescue a teeny tiny water bear, who doesn't mind the heat at all. |||||
| 75 | 3 | "Octonauts and the Cone Snail" | Shellington | 6 September 2013 |
| Only Peso can save the day when a cone snail invades the Octopod and tranquilizes the crew one by one with his dangerous venom-filled harpoons, turning them into googly-eyed Octonauts except Peso. |||||
| 76 | 4 | "Octonauts and the Artificial Reef" | Dashi | 9 September 2013 |
| When an underwater hurricane destroys a small reef, which a frogfish and other creatures depend on, Tweak and her crew must convert the recently destroyed Gup-F into an artificial reef before the second stage of the hurricane strikes! |||||
| 77 | 5 | "Octonauts and the Humpback Whales" | Barnacles | 10 September 2013 |
| When a sardine swallows the key to a treasure chest, a humpback whale helps Kwazii track her down. |||||
| 78 | 6 | "Octonauts and the Pelicans" | Kwazii | 11 September 2013 |
| When a floating garbage patch endangers a flock of pelicans and other sea creatures, the Octonauts and the birds work together to clean it up. |||||
| 79 | 7 | "Octonauts and the Sea Pigs" | Kwazii | 12 September 2013 |
| The Octonauts must stop a huge herd of sea pigs before they march blindly into the Mariana Trench - where there will be no access to food. But things get chaotic eventually when Tunip goes missing! |||||
| 80 | 8 | "Octonauts and the Yeti Crab" | Tweak | 13 September 2013 |
| As Tweak tests the Gup-X deep down in the Midnight Zone, a yeti crab cuts a vital electrical wire in the ship and cuts off all power, endangering himself and the Octonauts. |||||
| 81 | 9 | "Octonauts and the Barracudas" | Dashi | 10 March 2014 |
| Shellington and the Vegimals are on a mission to replant a mangrove forest that is put in peril by a school of toothy barracudas. |||||
| 82 | 10 | "Octonauts and the Duck-Billed Platypus" | Kwazii | 11 March 2014 |
| While rescuing river creatures after a storm, the Octonauts find a strange egg and come under attack by stinging platypuses. |||||
| 83 | 11 | "Octonauts and the Sea Skaters" | Dashi | 12 March 2014 |
| When Kwazii gets lost at sea aboard the tiny octo-ski, he meets a flotilla of even tinier sea skaters, the only insects of the ocean. But when the Octopod gets covered in plankton by giant waves and the Octo-Hatch won't open, Barnacles and the rest must save their ship once again! |||||
| 84 | 12 | "Octonauts and the Mudskippers" | Barnacles | 13 March 2014 |
| The Octonauts attempt to keep the peace amongst a trio of mudskippers whose home has been flooded. |||||
| 85 | 13 | "Octonauts and the Harbour Seal" | Dashi | 14 March 2014 |
| When Peso's patient, a remora fish, mysteriously disappears, the Octonauts enlist a unique undersea detective - a harbour seal. |||||
| 86 | 14 | "Octonauts and the Lion's Mane Jellyfish" | Peso | 17 March 2014 |
| An enormous lion's mane jellyfish gets his amazingly long tentacles tangled in the Octopod's engine whilst Tweak is working on it and causes havoc. |||||
| 87 | 15 | "Octonauts and the Red Rock Crabs" | Dashi | 18 March 2014 |
| Shellington and the others round up some lost crabs and marine iguanas that have got marooned on an island far too cold for them and take them home to the Galápagos Islands. |||||
| 88 | 16 | "Octonauts and the Sea Sponge" | Peso | 19 March 2014 |
| Examining a sick sea sponge, Peso is surprised to discover that all sorts of creatures live inside her, treating her like a hotel, a behaviour known as commensalism. |||||
| 89 | 17 | "Octonauts and the Immortal Jellyfish" | Tunip | 20 March 2014 |
| While caring for sea creatures, Peso discovers an adult immortal jellyfish named Dorian that changes into a baby when he was scared by predators. Captain Barnacles, Kwazii, and Peso guard Dorian at a distant reef, so Shellington rushes to photograph him damaging the GUP-E and booster packs in the process. |||||
| 90 | 18 | "Octonauts and the Urchin Invasion" | Kwazii | 21 March 2014 |
| Kelp-eating red sea urchins attack a kelp forest. The Octonauts are helped by Shellingtons's sister, Pearl, another sea otter and scientist, and her newborn son, Periwinkle. |||||
| 91 | 19 | "Octonauts and the Hammerhead Sharks" | Dashi | 21 September 2015 |
| When the day turns dark, the Octonauts study a group of baby hammerhead sharks as they hunt. |||||
| 92 | 20 | "Octonauts and the Loggerhead Sea Turtle" | Tweak | 22 September 2015 |
| After an undersea tremor separates the Gup-X and its crew, Barnacles seeks guidance from a mysterious sea turtle called a loggerhead. |||||

### Series 4 (2015–2016)

A fourth series of 24 episodes started being broadcast by CBeebies on 23 September 2015 and ended 14 June 2016. The episodes were released on Netflix on 15 October 2018.
Written by: Gabe Pulliam, Gordon Brassack, Kevin Burke, Nicole Dubuc, Rich Fogel, Kevin Hopps, Charlie Howell, Mark Huckerby, Adam Idelson, Sam Morrison, Nick Ostler, Kevin Seccia, Scott Sonneborn, Dean Stefan, Len Uhley, Greg Weisman, and Chris Wyatt
| No. overall | No. in series | Title | Octo-Alert sounded by | Original release date |
| 93 | 1 | "Octonauts and the Poison Dart Frogs" | Barnacles | 23 September 2015 |
| The Octonauts find out about poison dart frogs after a dangerous tidal bore sweeps up the Amazon, depositing all the fish high up in the trees! Thankfully, Tweak's new GUP, the GUP-H, was ready to help. |||||
| 94 | 2 | "Octonauts and the Hidden Lake" | Barnacles | 24 September 2015 |
| When Barnacles, Kwazii, Peso, and Shellington find a mysterious hidden lake underneath Antarctica, Shellington is eager to find some new undiscovered creatures living in the red water. But why is the lake red? And are there actually any creatures living down so deep in the ice? |||||
| 95 | 3 | "Octonauts and the Octopod Mystery" | Barnacles | 25 September 2015 |
| After the Octopod breaks down, Tweak knows that the only way to get the new part that she needs is to take a trip to the old Octopod. But they may not be alone in their abandoned ship... but they find that a giant Pacific octopus living there! |||||
| 96 | 4 | "Octonauts and the Baby Sea Turtles" | Dashi | 28 September 2015 |
| As newborn baby sea turtles make their way to the ocean, the Octonauts must help them avoid predators when a large wave threatens the island where the precious eggs are buried - not that they'll admit it! |||||
| 97 | 5 | "Octonauts and the Walrus Pups" | Orson and Ursa | 29 September 2015 |
| Captain Barnacles' niece and nephew Ursa and Orson are going to get their Polar Scout Badges when they spot three walrus pups on a drifting floe which is on a crash-course with two icebergs. Will Captain Barnacles be able to save them and finally earn the Walrus Rescue Badge - the only one he hasn't got? |||||
| 98 | 6 | "Octonauts and the Mantis Shrimp" | Two Mantis shrimps (accidentally) | 30 September 2015 |
| The Octonauts must get two mantis shrimp to stop fighting before their powerful claw strikes destroy the Octopod. |||||
| 99 | 7 | "Octonauts and the Loneliest Whale" | Dashi | 1 October 2015 |
| The Octonauts follow a strange song to a lonely humpback whale who is alone because he does not sound like the other whales! They have to help him because if nobody understands him, he won't find the way to the feeding ground. |||||
| 100 | 8 | "Octonauts and the Tree Lobsters" | Barnacles | 2 October 2015 |
| A storm washes Peso onto a mysterious, rocky island where he meets a band of lobster-like insects thought to be extinct. But he and the Octonauts must catch a baby tree lobster that ended up in the Octopod and bring him back to Balls Pyramid. |||||
| 101 | 9 | "Octonauts and the Convict Fish" | Barnacles | 14 December 2015 |
| The Octonauts evacuate the creatures living around a reef before a large archway collapses, but one stubborn convict fish refuses to move from her burrow! |||||
| 102 | 10 | "Octonauts and the Emperor Penguins" | Barnacles | 16 December 2015 |
| The Octonauts journey across a dangerous expanse of ice to help a penguin mother get back to her family, but they lose contact along the way. |||||
| 103 | 11 | "Octonauts and the Baby Gator" | Barnacles | 14 March 2016 |
| A baby alligator named Nipper stows away on the Gup K. Now the Octonauts must rescue him after he and Kwazii are swept out to sea. |||||
| 104 | 12 | "Octonauts and the Bomber Worms" | Barnacles | 14 March 2016 |
| While diving down to the Midnight Zone, the Octonauts are attacked by bomber worms and are enlisted to rescue an injured member of their troop. |||||
| 105 | 13 | "Octonauts and the Crawfish" | Barnacles | 22 March 2016 |
| When a population of crawfish is stricken by illness, the Octonauts race to find a cure. |||||
| 106 | 14 | "Octonauts and the Surfing Snails" | Barnacles | 22 March 2016 |
| When surfing snails are swept out to sea, it's up to Dashi and the Octonauts to save them. |||||
| 107 | 15 | "Octonauts and the Flamingos" | Barnacles | 4 April 2016 |
| The Octonauts find a lost flamingo chick separated from his family and they have to return him there before hungry alligators do! |||||
| 108 | 16 | "Octonauts and Operation Cooperation" | A carrot | 4 April 2016 |
| After Shellington crashes the GUP-D, 3 times in a row, he and Kwazii team up with moray eels and grouper fish to help pick up the pieces and fix the vehicle before daylight occurs. |||||
| 109 | 17 | "Octonauts and the Kelp Monster Mystery" | Barnacles (ambiguous) | 4 June 2016 |
| Dashi teams up with her little sister Koshi to help the Octonauts solve a mysterious disappearance in the kelp forest. |||||
| 110 | 18 | "Octonauts and the Yellow Bellied Sea Snakes" | Kwazii | 5 June 2016 |
| When Peso gets stranded on a beach with a mass of poisonous snakes after a terrible storm, one of the yellow-bellied snakes has a splinter of driftwood stuck in her scales, and Peso has a broken flipper (According to the UK version, meanwhile the US Version indicates that he got stung). Now the Octonauts must somehow get them back to the ocean by cooling them off with water and building a swimming pool and save Peso! |||||
| 111 | 19 | "Octonauts and the Coconut Crisis" | Clarence the coconut crab | 6 June 2016 |
| Kwazii takes a vacation on Coconut Island where he gets hit by some coconuts. Then he and the Octonauts must help their old friends the coconut crabs discover who's stealing all their coconuts. |||||
| 112 | 20 | "Octonauts and the Coelacanth" | Barnacles | 7 June 2016 |
| While exploring a dark and spooky cave, The Octonauts find a strange fossil of a powerful prehistoric fish... but he may be more than just a fossil! |||||
| 113 | 21 | "Octonauts and the Tiger Shark" | Kwazii | 8 June 2016 |
| When a hungry tiger shark whose name is Tom eats the camera that Tweak's leatherback sea turtle friend Sandy gets in the Octopod, she and the Octonauts must rescue her before he eats everything in his path. |||||
| 114 | 22 | "Octonauts and the Hippos" | Shellington (in his sleep) | 9 June 2016 |
| Trying to return home from a mission along an African river, the Octonauts have trouble getting past a gang of large, mud-splatting, territorial hippos. |||||
| 115 | 23 | "Octonauts and the Spinner Dolphins" | Barnacles | 13 June 2016 |
| The Octonauts struggle to save a pod of spinner dolphins who seem to be just swimming in their sleep. |||||
| 116 | 24 | "Octonauts and the Sunfish" | Dashi | 14 June 2016 |
| When a huge sunfish by the name of Sonny enters the GUP-E, Peso, and Kwazii must somehow get the large fish out of the Gup. Eventually, they find out it's a sunfish by the name of Sonny; a species of fish with no fins. |||||

### Series 5 (2023)

A fifth series of 50 episodes started being broadcast on CBeebies on 27 March 2023.
| No. overall | No. in series | Title | Octo-Alert sounded by | Original release date |
| 117 | 1 | "Octonauts and the Bluefin Tuna" | Kwazii | 27 March 2023 |
| 118 | 2 | "Octonauts and the Blue Whale Rescue" | Kwazii | 28 March 2023 |
| 119 | 3 | "Octonauts and the Whales of Mystery" | Shellington | 29 March 2023 |
| 120 | 4 | "Octonauts and the Ghost Ship" | Barnacles | 30 March 2023 |
| 121 | 5 | "Octonauts and the Feeding Frenzy" | Barnacles | 31 March 2023 |
| 122 | 6 | "Octonauts and the Sawfish" | TBA | TBA |
| 123 | 7 | "Octonauts and the Nautilus" | TBA | TBA |
| 124 | 8 | "Octonauts and the Grey Whales" | TBA | TBA |
| 125 | 9 | "Octonauts and the Flying Squid" | TBA | TBA |
| 126 | 10 | "Octonauts and the Sea Lions" | TBA | TBA |
| 127 | 11 | "Octonauts and the Hawksbill Sea Turtle" | TBA | TBA |
| 128 | 12 | "Octonauts and the Wood Eating Catfish" | TBA | TBA |
| 129 | 13 | "Octonauts and the Seven Sea Squirts" | TBA | TBA |
| 130 | 14 | "Octonauts and the Bullfrogs" | TBA | TBA |
| 131 | 15 | "Octonauts and the Giant Sea Spider" | TBA | TBA |
| 132 | 16 | "Octonauts and the Great Octo-Bot Rescue" | TBA | TBA |
| 133 | 17 | "Octonauts and the Axolotl" | TBA | TBA |
| 134 | 18 | "Octonauts and the Beavers" | TBA | TBA |
| 135 | 19 | "Octonauts and the Zombie Worms" | TBA | TBA |
| 136 | 20 | "Octonauts and the Mud Volcanoes" | TBA | TBA |
| 137 | 21 | "Octonauts and the Tiger Fish and Blind Shrimp" | TBA | TBA |
| 138 | 22 | "Octonauts and the Fish Mouth Louse" | TBA | TBA |
| 139 | 23 | "Octonauts and the Deep Ocean Discovery" | TBA | TBA |
| 140 | 24 | "Octonauts and the Silver Sea" | TBA | TBA |
| 141 | 25 | "Octonauts and the Bicolour Fangblenny" | Barnacles | TBA |
| 142 | 26 | "Octonauts and the Scaly-Foot Snail" | TBA | TBA |
| 143 | 27 | "Octonauts and the Chinese Giant Salamander" | TBA | TBA |

## Specials

The specials are double-length episodes that are first broadcast during the Christmas, New Year, or Memorial Day periods before being repeated alongside regular episodes.
| No. | Title | Octo-Alert sounded by | Original release date |
| 1 | "Octonauts and the Great Penguin Race" | Kwazii | 13 December 2010 |
| Peso is going home to Antarctica to watch an annual penguin triathlon, the Iron Clam Competition, but learns to his dismay that his little brother Pinto has entered him in it. With the Octonauts cheering him on, Peso will have to slide, dive and swim his way to victory, against the annual athletic winner, Hugo. ||||
| 2 | "Octonauts and the Great Christmas Rescue" | Inkling | 22 December 2011 |
| The Octonauts travel for Christmas to Professor Inkling's childhood home, a seamount, but soon get involved in a rescue mission when a rockslide endangers a rare 500-year-old golden coral and traps Professor Inkling's nephew Squirt. They also learn about Christmas tree worms which live in holes in rocks. Crucial to completing the mission is the new heavy-duty vehicle GUP-X which Tweak has built as an early present for Captain Barnacles. ||||
| 3 | "Octonauts and the Amazon Adventure" | Kwazii | 1 January 2013 |
| Kwazii enters a shipwreck to get Calico Jack's map to an underwater city of gold. This leads the Octonauts up the Amazon River, past parrots, freshwater stingrays, caiman and manatees. But a falling tree traps the GUP-A, and a tidal bore comes up the river, scattering the octonauts. Captain Barnacles looks for the others with the aid of a river dolphin and its echolocation abilities. The Octonauts help an electric eel, a stranded arapaima, and get chased by piranhas. But a wood-eating panaque frees the trapped GUP-A. Meanwhile, Kwazii has been saved by Calico Jack who turns out to be alive but lost his ship after an attack by fire ants and an anaconda. His incomplete map had led him in circles, but Kwazii's piece completes it so they can finish the quest. After being blocked by hostile capybaras, they are reunited with the others in time to fight off more anacondas. Finally the "city of gold" turns out to be a colony of golden freshwater sponges in the bottom of a pool. ||||
| 4 | "Octonauts and the Mariana Trench Adventure" | Barnacles | 27 May 2013 |
| The Octonauts assemble Tweak's new Deep Sea Octolab and lower it to the deepest part of the ocean, the Mariana Trench, where Shellington and Dashi intend to study the sea life. Whilst the Octonauts are setting up the base it is invaded by some giant isopods and other creatures which are looking for a new hydrothermal vent to live around (and accidentally knocking out the power source in the process). They also observe some sea cucumbers and luminous sea stars, and whilst chasing an out-of-control Octobot Robots & Vegebot after a power surge cause them to go out of control, Kwazii has to avoid undersea mud volcanoes which have created a lake of hot mud on the seafloor and lava. ||||
| 5 | "Octonauts and a Very Vegimal Christmas" | Tunip (thrice; only Vegimals attend) | 17 December 2013 |
| When nearly all of the Octonauts are trapped in a dangerous sentient blob of marine mucilage, the only Octonauts not trapped in the blob, the Vegimals, must step up and build a new GUP called the GUP-V to rescue the crew in time for their Christmas meal. ||||
| 6 | "Octonauts and the Over, Under Adventure" | Shellington | 14 March 2014 |
| The Octonauts' mission to explore Antarctica during which they marvel at sea tulips and hourglass dolphins becomes a desperate rescue as a group of sea stars and urchins are threatened by a brinicle - a rare underwater icicle that can freeze creatures on the sea bed. So the crew use the recently built GUP-S to save the day, with the help of a Weddell seal. ||||
| 7 | "Octonauts and the Great Arctic Adventure" | Barnacles | 22 April 2014 |
| While the Octopod is at the base for repairs, the Octonauts (except for Inkling, Tweak, and Tunip) take vacations for themselves. Captain Barnacles and Peso visit his sister Bianca at her den and helps her two cubs Orson and Ursa to find the sea ice during the springtime migration and call on the rest of the Octonauts to rescue fellow polar bears from Norway, Canada, Greenland, Alaska, and Russia as their ice floe was melting. ||||
| 8 | "Octonauts and Operation Deep Freeze" | Barnacles | 15 December 2015 |
| Captain Barnacles runs into an old friend - an Arctic fox named Professor Natquik - in Antarctica. They must work together with the other Octonauts to prevent a group of penguins from falling into an ice chasm. ||||
| 9 | "Octonauts and the Great Swamp Search" | Barnacles | 28 March 2016 |
| Tweak and the Octonauts go to The Everglades to visit her dad, Ranger Marsh, and help him rescue some non-native creatures before a storm hits. The team's recently built GUP-K is also there to save the day when a fire spreads. ||||
| 10 | "Octonauts and the Caves of Sac Actun" | Dashi | 14 August 2020 |
| The Octonauts embark on an underwater adventure navigating a set of challenging underwater caves, with help from a new friend, to help a small octopus return home to the Caribbean Sea. ||||
| 11 | "Octonauts and the Great Barrier Reef" | Barnacles | 13 October 2020 |
| In this musical special the Octonauts must find a way to hold back hungry swarms of Crown of Thorns starfish to save a new friend's fragile reef home. ||||
| 12 | "Octonauts and the Ring of Fire" | Tweak and Kwazii | 30 March 2021 |
| When red-hot volcanoes start a chain reaction of disasters across the ocean, the Octonauts must work together to face their biggest challenge yet. They use the recently created Z-GUPs, (the Z1, Z2, Z3, Z4 and Z5), to save many creatures, including an Omura's whale, some chinstrap penguins, and many more creatures from various volcanoes and one giant volcano. ||||