Islands of the Southern Ocean

The Southern Ocean is the very cold ocean surrounding Antarctica and bathing several archipelagos. There are various definitions of its extent, but this page describes islands south of or close to the Antarctic Convergence, out to about 50°S. They are all difficult to reach, as much through their remoteness as their cold climates. See polar explorers for the exploration of the region, mainly in the late 19th and early 20th centuries. == Antarctic islands == The Antarctic islands lie south of the 60th parallel and are governed by the Antarctic Treaty. East to west are: 1 Balleny Islands are part of the Ross Dependency of New Zealand. The three main islands (all about 25 km long by 3 km wide, and ice-clad) are Young, Buckle and Sturge. There's no base here and since their discovery in 1839, humans have only set foot on them on four occasions. 2MISSING WIKILINK South Orkney Islands largest member is Coronation Island, discovered in 1821 and named for newly-crowned King George IV of Britain. It's 46 km long and about 10 km wide, with Mount Nivea its highest peak at 1266 m. It's almost entirely ice-clad, with a few ice-free patches along the coast, and is a breeding ground for chinstrap penguins, Cape petrels and snow petrels. Signy Island to the south has a British research station, staffed in summer. Laurie Island to the east has the Argentine station Orcadas, staffed year-round. Powell and Fredriksen are the other two significant islands, lying between Coronation and Laurie islands. 3 Peter I Island in the Bellingshausen Sea is a dependency of Norway. It was first sighted in 1821 but is usually hemmed in by pack ice, so the first landing was only in 1929. It's 11 km long by 19 km broad, about the size of Staten Island. It's mostly covered by glacier, with a 1640 m mountain, and has no base. 4 Scott Island, discovered in 1902, is part of the NZ Ross Dependency. It's only 565 m long by at most 340 m wide and has no base. In 2009 a couple were married here by their ship's captain, so Barbados is facing more competition. == Sub-Antarctic islands == These islands north of the 60th parallel are governed by different countries. East to west are: 5 New Zealand Subantarctic Islands are in five groups: The Snares, Bounty Islands, Antipodes, Auckland Islands and Campbell Island. 6 Macquarie Island, part of Tasmania in Australia, is a wildlife reserve 20 miles long by 3 miles wide. 7 Heard Island and McDonald Islands are a territory of Australia, with that nation's only active volcanoes, last erupting in 2016. The archipelago is also a UNESCO World Heritage Site. 8 Kerguelen is part of the French Southern and Antarctic Lands. The main island Grande Terre is 150 km east-west by 110 km north-south and has a permanent scientific settlement. There are some 300 lesser isles in the archipelago. 9 Crozet Islands are a French archipelago, with the research station Alfred Faure on Île de la Possession. 10 Prince Edward Islands are part of South Africa, 1200 miles southeast of the Cape, with Marion Island the larger and Prince Edward the smaller island. 11 Bouvet Island is Norwegian, ice-clad, and volcanic though with no recent eruptions. 12 South Georgia and the South Sandwich Islands are administered by Britain. South Georgia is icy and mountainous, with the old whaling stations of Grytviken and South Leith. The South Sandwich Islands are volcanic and stretch almost to the 60th parallel, so they're on the threshold of Antarctica and very difficult to access. == Other == 13 Falkland Islands are not within the Southern Ocean, but are marked on the map to show the vagaries of its boundaries. They're closer to the pole than several islands considered "sub-Antarctic" but although chilly, they're never ice-bound. Tierra del Fuego at the tip of South America is similar. == Understand == About 15 million years ago, the mountain chain connecting South America to Antarctica sank under the ocean, and a new continent was born. Cold sea currents enclosed Antarctica and its climate became intensely cold. The oceanography and biology of those currents was poorly understood until 21st century technology such as satellite imaging probed remote waters and depths beyond human reach. It's now recognised as "the Southern Ocean", a body of water as distinct as the Atlantic and Pacific. It has no east-west boundary, but circulates clockwise (west to east) around Antarctica, with the gales of the Screaming Sixties raising huge waves with no land to break them. Its northern boundary is invisible but distinct: a 30 km strip where it meets the other oceans but does not much mingle, and a great upwelling of deep water drives a food chain. This "Convergence" is at roughly 60°S where it meets the Pacific, and this was an earlier definition of its extent, but is around 50°S meeting the Atlantic and Indian Oceans. Seafarers know they've reached it when those aboard declare "Jeez, and I thought I was cold yesterday." The Antarctic islands lying south of the 60th parallel have a marine polar climate: very cold, but not as extremely cold as the mainland, so the sea only freezes over in the very depths of winter. They are all governed by the Antarctic Treaty, which (as on the mainland) seeks to protect the fragile environment, forbids military use, and sets aside national claims. Thus, various nations operate bases here and have hypothetical claims to territory which they waive. References to nations on this page should be understood accordingly. The Treaty restricts commercial activity but doesn't affect fishing on the open ocean. Sub-Antarctic islands are also cold but not polar deep freeze: modulated by the ocean, their midsummer temperature is about 5–10 °C (40–50 °F) and their winters average 0 to −10 °C (32–14 °F). That makes them more approachable by ship, and they're often the first or last points of call of cruises into Antarctica. It's not their coldness but their remoteness and lack of population and amenities that put them beyond the range of individual travel, so you need to join an expedition, cruise or similar organised party. They're not covered by the Treaty but are designated as nature reserves by their governing nations, and have bases but no permanent residents. This page doesn't cover islands which lie close to the Antarctic mainland (often welded to it by thick ice) and are described elsewhere. Along the Antarctic Peninsula, these include Anvers and Wiencke islands, with Port Lockroy; on the other side of the continent is Ross Island, with McMurdo base and Scott base. Nor does this page cover the islands close to mainland South America, the Falkland Islands and Tierra del Fuego. They have towns, places to stay and eat, and regular transport. Many people visit them as part of an organised trip down into Antarctica but you can get yourself there independently. You'll need warm clothing but the descriptions and advice for the sub-Antarctic islands doesn't apply to them. == Get in == Visiting this area of the world involves careful planning, a big budget, several weeks or months of your time, and incurs risks. Most visitors are on organised tours or cruises, and planning your own expedition is beyond the scope of these pages. Visitors to any land or sea south of 60°S need permission from an Antarctic Treaty member country. Your tour or cruise organiser will take care of this but those travelling independently should apply six months in advance. Individual, non-governmental visitors can contact the Antarctic Policy Unit, Ministry of Foreign Affairs and Trade, Private Bag 18901, Wellington NZ, phone +64 4 439 8000. The formalities north of 60°S are similar, check with the governing nation. === By boat === It's not too difficult to reach the islands that are near a regular cruise route to Antarctica and with a harbour or at least a sheltered beach that a Rib (Zodiac) can access. They are routinely visited by cruises in summer: see Antarctica#Get in for options. Cruises from Ushuaia in Tierra del Fuego towards the Antarctic Peninsula often take in South Georgia, and those from New Zealand towards the Ross Sea might take in the NZ Group or Macquarie. The Antarctic cruises from Ushuaia take a couple of weeks and cost over US$5000 per person. At the other end of the scale, islands far from a cruise route and lacking harbours are very challenging to reach, and then there's the getting out to consider, when storms may render the landing beach unusable for weeks on end. Bouvet Island is one bleak and daunting example. Some of these places have only been reached by a handful of people in the 250 years since they were discovered. Midpoint on the scale of difficulty is Kerguelen. A regular supply ship sails from Réunion, making a one-month circuit of the heaving ocean and also calling at Crozet and Amsterdam Island. It carries research and support staff but no longer carries tourists. You may need official permission to land, or even to sail close to shore – this is chiefly to protect the wildlife. Cruise operators and expedition organisers are responsible for arranging this, and it may need to be sorted several months in advance. === By plane === Villa las Estrellas (TNM IATA) on King George Island in the South Shetlands, 150 km north of the Antarctic Peninsula, has a gravel all-seasons runway suitable for large wheeled aircraft. Flights from Punta Arenas take about 4 hours. There are no commercial scheduled flights, but there are air tours, and transfers of visitors joining small-ship cruises. == Get around == A few of these islands are compact and walkable: Scott Island is a scrap 565 m long. South Georgia by contrast is 170 km long, riven by glaciers and mountains (some still unclimbed); there are hiking trails near its main base of Grytviken, but beyond those is expedition territory. You need a boat (a Rib for short hops, or your support vessel for further afield) not only to move between islands, but to move along these rugged coasts with no inland trails. == See and do == As with mainland Antarctica, even just standing there looking is going to involve exertion on your part, careful preparation, and a degree of risk. The distinction between seeing and doing disappears here, and your prime task is to come home safe. Don't do anything, not even just standing there, without having that objective in mind. No trees: Antarctic and sub-Antarctic scenery lacks trees and shrubs, and resembles tundra. This means that birds (including penguins) nest on open ground, where they are vulnerable to rats or visitor disturbance. The islands have rocky outcrops and tussocky grasslands; there may be ice caps at high elevations, but not on low ground. Sea life includes seals and whales. They were once hunted commercially, and some islands have the rusty ruins of old whaling stations. Penguins: Huge penguin colonies are found on many of the islands, and some species have their principal habitat here rather than on the mainland. Volcanoes are active on Heard Island and the McDonald Islands, and along the chain of South Sandwich Islands. Their active history is only partially known, as it's only in the 21st century that satellite imaging has spotted their belchings of steam and ash. Penguins are fond of volcanoes, as the geothermal warmth creates areas free of glaciers. Huge icebergs – defined as 20 km or more across – are common around Antarctica, and may last for decades, but most remain pinned within the pack ice. A few escape, and the largest may reach the sub-Antarctic islands and shipping lanes of these latitudes, so they're tracked by the US Ice Center. A good example was A68a, which in 2021 approached South Georgia before breaking up. "A" means it calved in the quadrant between 0° and 90° West, the Bellingshausen and Weddell seas – in this case it was the Larsen Ice Shelf on the west coast of the Peninsula. B-icebergs are from the quadrant 90° to 180° West, and so on round. A68 means it was the 68th iceberg from Quadrant A, and when it broke into pieces that were huge in their own right, these were labelled A68b, c, d etc, with the mother-berg being A68a. Its end was unexpected: it didn't gradually fracture, but suddenly foamed and fizzed away like a colossal Alkaseltzer. Probably day-time melt water permeated it to freeze and expand at night, pushing open the cracks for the next day's melt water, until there was massive structural failure. So A68a has given us insight into how other bodies of ice might suddenly destabilise. A23a was the size of Mallorca as it passed South Georgia in 2025 / 26, before disappearing in the South Atlantic. == Buy, eat and drink == You must bring everything you need with you and take everything away, especially trash. There are fresh water sources in summer, but the birds will get there first and foul it. == Sleep == Most visitors sleep on their cruise ship. Sleeping ashore makes the trip an expedition, which needs to be self-sufficient: the bases have enough rations for their crew but can't cater to tourists. Some air tours have their own campsite, for instance on King George Island. == Stay safe == The environment is extreme, with latitudes called the roaring forties, filthy fifties and screaming sixties for good reason. Storms sweeping off Antarctica, unobstructed by any land, bring cold strong winds, rain or snow and rough seas to the region. This part of the world is the preserve of deep sea fishing ships (not boats), warships on fisheries patrols, oceanographic research ships, round-the-world yachts and the occasional icebreaker on its way to Antarctica. If you get into trouble, you must be prepared to rescue yourself, as emergency rescue services may be thousands of miles and several days away. == Connect == Surprise surprise, there's no mobile or Wi-Fi signal in these remote waters. Ships use satellite phones and charge for brief access. There's a Post Office at Villa Las Estrellas on King George Island. == Go next == Cruises visiting the islands of the Southern Ocean are usually making their way to Antarctica or returning across huge seas, with everyone upchucking and the buffet strangely quiet.