Agreement was reached by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) - which is made up of 24 countries including the UK - and the EU, to protect 600,000 square miles of the Ross Sea.
The protected area, which will come into force in December 2017, will curb damaging activities such as fishing to protect wildlife including Adelie and emperor penguins in the remote Antarctic sea.
Some 72 per cent - 430,000 square miles - of the marine protected area will be a “no-take” zone where all fishing is forbidden, while other areas will allow some harvesting of fish and krill for scientific research.
Last year British endurance swimmer Lewis Pugh completed a series of swims in the freezing waters around Antarctica to call for a marine reserve to protect the “pristine” waters of the Ross Sea.
It is one of the last intact marine ecosystems in the world, which Mr Pugh described at the time of his swims as a “garden of Eden”. The sea is home to penguins, Weddell seals, Antarctic toothfish and killer whales.
The deal, put together by New Zealand and the US, became a reality after Russia - the last country holding out on the creation of the protected area - agreed to the move.
Rod Downie, polar programme manager for wildlife charity WWF, said: “This is a milestone for the conservation of Antarctica and the Southern Ocean. After a decade of negotiations, we have agreement on the protection of the Ross Sea.
“Members of CCAMLR have worked tirelessly to secure this deal - but this is just the start.
“The current measures only extend for 35 years. We want a permanent and enduring agreement for future generations that will safeguard the whales, penguins, seals and thousands of other amazing species that live there”.
“The deal will help to ensure the conservation of globally important ocean habitats as well as providing research opportunities and increasing the Southern Ocean’s resilience to climate change.”
Andrea Kavanagh, from the Pew Charitable Trusts, said: “CCAMLR made history today by declaring the world’s largest marine protected area in the Ross Sea, protecting penguins, seals, whales and countless other creatures.”
John Hocevar, a marine biologist with Greenpeace, said: “This is a victory for the whales, toothfish and penguins that live in the Ross Sea, as well as for the millions of people who supported this effort.
“We urge the international community to take notice and designate additional, permanent protections in other areas of the Antarctic Ocean and around the world.”