Chelsea/The Lost Birthday

Chelsea Roberts is a character in Barbie Dolphin Magic. She is voiced by Ciana Swales. Chelsea and her sisters go to an island to visit Ken during his marine biology internship. They befriend a mermaid named Isla and help her to free the Gemstone Dolphins from the research facility where Ken works.
== Story ==
Chelsea and her sisters go to an island to visit Ken during his marine biology internship. They bring their puppies with them. The girls arrive at the island's resort and go to their cabin. Chelsea sees that the cabin has a slide, so she changes into her swimsuit and puts on her floatation ring, Mr. Floatie. 
Ken greets the girls at their cabin, and Chelsea asks him if he's seen any mermaids yet. Skipper says mermaids aren't real, but Barbie says not seeing mermaids doesn't mean they don't exist. Chelsea asks Ken if he's seen any dolphins, but he says no. Ken invites the girls to see the reef with him. Stacie can't go because of a sprained ankle. Chelsea stays at the cabin keep Stacie company. Barbie, Ken and Skipper leave with the puppies.
While Chelsea plays on the slide, Stacie looks around the island using binoculars. Chelsea borrows the binoculars and sees a green Gemstone Dolphin named Emerald. It is being kept at the research facility where Ken works. Chelsea and Stacie go to the facility to look at the dolphin. At the reef, Barbie, Ken and Skipper catch a glimpse of a mermaid named Isla. Skipper takes a blurry photo of her. They follow Isla and end up at the facility at the same time as Chelsea and Stacie. Isla hides when she hears the speedboat approaching. 
Ken says that Emerald is in the pool for sick animals, but Barbie thinks he looks must have got in by accident because he looks fine. She tries to free Emerald, but she is stopped by Ken's boss, Marlo. Ken asks Marlo if Emerald is a Gemstone Dolphin, but she says they're not real. Ken says that means they're like mermaids, so Chelsea replies that mermaids are real. Barbie tells her that anything is possible. Marlo says a vet will be flying in to check on Emerald the following day, and she tells everyone to leave. Chelsea wants to stay, but Marlo insists that everyone leave. 
On the way back to the cabin, Chelsea realizes the puppies are missing. Barbie goes back to the facility to get them. Isla uses a necklace to turn her tail into legs, and tries to free Emerald. Barbie stops her, but Isla says Emerald is green because he is a Gemstone Dolphin, not because he is sick. She says she knows a few more Gemstone Dolphins. Barbie tells Isla that a vet is coming the next day, so Isla agrees to wait for the vet, as long as Barbie doesn't tell anyone about Gemstone Dolphins. Barbie invites Isla back to the cabin, and introduces her to Chelsea, Skipper and Stacie. 
Chelsea gives the puppies treats and asks Isla about herself. After Isla says she has no sisters, Chelsea replies that she is lucky because she won't get hand-me-downs. They go to the resort's sandwich bar to eat. In the evening, Chelsea and her istsers go back to the sandwich bar with Isla. They meat up with Ken, and Skipper takes a group selfie. Chelsea makes a beat with a coconut shell, and her sisters join in to make a song. Barbie invites Isla to have a sleepover with them. 
At the cabin, Chelsea has a pillow fight with her sisters. Isla falls asleep quickly. Chelsea tries to wake her up in the morning, but Isla sleeps until Barbie mentions food. Chelsea and her sisters get breakfast sandwiches with Isla, and then Chelsea goes back to the cabin with her sisters. Barbie and Isla go swimming. The Gemstone Dolphins find them, and one of them touches Isla's necklace. Isla's legs transform back into a mermaid tail. Barbie promises not to tell anyone, not even her sisters. 
Stacie uses her binoculars and sees Marlo waving in a helicopter. She assumes that the pilot, Hugo, is the vet. Chelsea asks her why she's still using the binoculars even though her ankle feels better. Stacie says they should go find Barbie and tell her the vet has arrived. While Chelsea and her sisters look for Barbie, they get a closer look at the helicopter. Chelsea thinks the walrus logo on the helicopter is cute, but Skipper thinks it is a weird logo for a vet.
Chelsea and her sisters overhear Marlo and Hugo discuss how they will make money off of Emerald. The girls realize Hugo is not really a vet, so Skipper takes a photo of the helicopter logo. Isla and the Gemstone Dolphins find an underwater cave and wonder if it leads to the facility. The dolphins go to the facility to find Emerald, and Marlo gives Ken a code to open the gate. She orders Ken to close the gate after the dolphins swim in. She locks the gate using a remote,and then leaves to call Hugo. 
Chelsea and her sisters overhear Marlo telling Hugo that she needs more nets to transport the dolphins to the mainland facility. Skipper uses her tablet to make her photo of Isla clearer, and the girls see that it is a mermaid. However, Isla's face is not visible in the photo, so they don't know it's her. At the facility, Isla tells Ken that Marlo has trapped the dolphins. He tries to use the code Marlo gave him to open the gate, but Marlo has changed it. Chelsea and her sisters arrive, and they tell Barbie that Marlo and Hugo suspicious. Chelsea tells Barbie that Skipper took a photo of a mermaid, and Barbie realizes it was Isla. 
Barbie comes up with a plan to help Isla free the Gemstone Dolphins. She tells Chelsea to distract Marlo with Ken and the puppies. At the sandwich bar, Ken distracts Marlo while she is eating. Chelsea puts a piece of cheese on Marlo's shoe, and Chelsea's puppy Honey tries to eat it. Marlo gets startled, and Chelsea uses the opportunity to take Marlo's remote. Chelsea hides the remote behind her back, and Marlo tells her to go play somewhere else. Chelsea gives the remote to Skipper, who syncs it to her tablet and gets the code. Chelsea returns the remote to Marlo's table. Marlo sees that her remote is dirty, so she realizes she has been hacked. She changes the code again.
At the facility, Isla thanks everyone for helping to get the code. Isla uses her necklace to turn her legs into a tail, and Chelsea is happy to see a real mermaid. Skipper tries to put in the code to free the dolphins, but it doesn't work. Marlo arrives and says she is going to use the helicopter to transport the dolphins. Isla hides underwater with the dolphins, and Marlo leaves, thinking that the dolphins have escaped. Isla resurfaces and says she found an underwater tunnel that may lead to the cave she found earlier. Isla plans to use shells from her magic necklace to create a trail of light, which merpeople and friends of mermaids use to find each other in the ocean. The light will help her to navigate the tunnels. Barbie goes to the cave, and uses the shell to light up the tunnel. 
Chelsea cheers when Isla's plan works. Isla and the dolphins manage to escape the facility through the tunnel. Marlo and Hugo pursue them in the helicopter. Ken uses the speedboat to escape with Chelsea, Isla and everyone else on board. When the water gets shallow, Isla says she has to get out and swim with the dolphins. Chelsea says they will miss her. Isla tells Barbie to keep the shell from her necklace, and and Isla turns her legs into a tail. Marlo sees Isla as a mermaid, and wants to capture her instead of the dolphins. 
Barbie quickly covers herself in seaweed and wears flippers so that her underwater silhouette looks like a mermaid. Marlo captures her instead of Isla, and Chelsea gets worried, unaware it is really Barbie. Isla and the dolphins swim to safety, and Barbie tells Marlo that she will lose her facility because she exploits animals. Later, at the beach, Chelsea builds a sandcastle. She names it Castle Malibu, and Ken gives her a flag to put on top of it. Barbie and Isla use the shells to find each other, so Isla comes to the beach with the dolphins. Chelsea gets excited to see Isla again, and they watch the dolphins swim.
== Physical Appearance ==
Chelsea is a girl with light skin, blue eyes and long blonde hair. Her casual outfit is a white tank top, blue shorts and green low-top sneakers. The top has a pineapple wearing sunglasses on it, and the word "VACATION." 
Chelsea also wears a colorful swimsuit that has a strawberry ice cream cone on it, with blue flip-flops. She has a pink and purple floatation ring that she calls Mr. Floatie. At the sleepover, she wears a light purple nightdress with ice cream cones on it. She also wears pink bunny slippers. On the speedboat, she has a yellow and purple lifejacket.
== Personality ==
Chelsea gets excited easily. She is encouraged by Barbie to believe anything is possible, even the existence of mermaids. Chelsea is very playful and pretends her floatation ring, Mr. Floatie, talks to her. Chelsea likes Isla, and is very curious about her. Chelsea tries to make her laugh, and helps her to save the dolphins. Chelsea is very close to her sisters, and they have a strong bond.
== Quotes ==
* (To Ken) "Have you seen any mermaids yet?!"
* "What's that, Mr. Floatie? You say you can't get enough of this slide? Well, neither can I!"
* "No fair, it's a bright green dolphin!"
* "Puppies, you're back! Who wants treats?"
* (To Isla) "Hi! I'm Chelsea. Where are you from? Are you on vacation? Do you have any sisters?"
* (After finishing her drink) "Ahh! That... was... epic!"
* (To Skipper and Stacie) "What? Now you're both people-watching? I thought Stacie getting out of the boot meant we could go do stuff."
* (After seeing Hugo's logo) "Aw... cute walrus!"
* (After seeing Skipper's photo of Isla) " It's a mermaid! It's a real mermaid...!"
* (After Skipper sees that mermaids are real) "See? I rest my case."
* (Before Isla leaves) "We're gonna miss you!"
* (About her sandcastle) "Castle Malibu, fit for a queen!"
== Trivia ==
*Chelsea also appears in the series Barbie Dreamhouse Adventures.
* Chelsea's nickname is Chels.