Australian activist Colin Russell has finally been released from a St. Petersburg detention center, the last of the Arctic 30 detainees to be freed on bail after the seizure of the Greenpeace International ship Arctic Sunrise more than two months ago.

With many of the world's media gathered around him, photos of Colin's release show him smiling and hugged by friends, finally freed. He was later reunited with his wife Christine and daughter Madeleine, who both flew into Russia on Friday.

Paul Myler, Australia's ambassador to Russia, was quick to welcome the news, tweeting: "Great result for Colin! Was getting worried that Friday afternoon, bureaucracy and paperwork might conspire against us!"

Colin's release is long overdue. More than 70 days ago, Russian security agents illegally boarded theArctic Sunrise in international waters, seizing the ship and detaining all those on board at gunpoint.

The ship was towed to Murmansk and all those on board were locked up in cold, filthy cells, some of them in solitary confinement. They were charged with piracy and then hooliganism, crimes that carried lengthy prison sentences.

Why? Because they dared to peacefully take action against destructive Arctic oil drilling and the onslaught of climate change, protesting at state-owned Gazprom's Arctic drill platform in the Barents Sea. They are neither pirates, nor hooligans. They are heroes.

Courts in St. Petersburg have since granted them bail and besides getting medical checks, they have talked to or had visits from loved ones and they are getting plenty of food, care and rest. As a group they are talking through the potentially traumatising experiences they have been through.

But they are still not allowed to leave Russia. They wait for Russia to comply with a binding ruling from an international court of law that ordered Moscow to allow them to leave Russia.

In a case lodged by the Netherlands, the International Tribunal for the Law of the Sea (ITLOS) ordered the Russian Federation on November 22 to release the ship and every detainee upon posting of a 3.6 million euro bond by the Netherlands.

The Netherlands, as flag State of the Arctic Sunrise, had argued at the Hamburg-based Tribunal that Russia had no right to board and detain the ship and all on board and that the detention of the crew is a violation of their right to liberty and security.

In developments on Friday, the Dutch Foreign Ministry said it had finalised the bank guarantee in compliance with the Tribunal's ruling. Russia is obligated to also comply with the ruling by releasing the ship and the Arctic 30.

Russia, however, has so far refused to participate in the proceedings at the Tribunal, invoking an exemption Russia added to its 1997 ratification of the UN Convention on the Law of the Sea (UNCLOS).

It neither attended the hearings on November 6, nor the November 22 ruling, instead leaving empty desks in a tribunal chamber presided over by 21 international judges. Never before has this happened at the Hamburg Tribunal.

Russia's non-appearance at the Tribunal hearing did not deter it, however, from reaching a decision. It eventually ruled in favour of the Netherlands and the release of the ship and its crew of 30.

Russia was not formally obliged to participate in the proceedings, but it is under an obligation to comply with any ruling the Tribunal makes. Such rulings are binding to any party to the UN Convention on the Law of the Sea -- including Russia.

This was a point underlined in an opinion article on Friday by Donald Rothwell, Professor of International Law at the Australian National University:

"Russia cannot ... pick and choose when it will and will not abide by the law of the sea. As a leading international citizen, it has a clear obligation to follow the Tribunal's ruling and release the Arctic Sunrise and its crew and to allow them to leave Russia. It should indicate its compliance with the Tribunal's orders as soon as possible."

Greenpeace does not disagree and assumes that Russia will comply with the ITLOS ruling and stands ready to welcome home our friends and activists as soon as they are allowed to leave.