The U.S. captain of the ship, veteran Greenpeace activist Peter Willcox, was among 18 freed on Friday. The others were released late Wednesday and Thursday.
"I feel like I'm down out of the tree but still in the forest," Willcox told journalists. "But it's a big step."
All 30 still face hooliganism charges, which carry a sentence of up to seven years. They were detained after some of the activists aboard the Arctic Sunrise attempted to scale an offshore drilling platform owned by the state-owned natural gas giant Gazprom.
Also Friday, a U.N.-mandated tribunal in Hamburg, Germany, ordered Russia to immediately release the Greenpeace ship and its crew in return for a 3.6 million euro ($5 million) bond.
The International Tribunal for the Law of the Sea also ordered Russia to allow the Dutch-flagged vessel and those detained to leave the country.
The Russian Foreign Ministry said in a statement that it would study the decision.
Greenpeace lawyer Mikhail Kreindlin said there was nothing in Russia's criminal procedural code that would prevent the foreigners from leaving Russia, but for most of them there was another problem: They come from countries whose citizens need a visa to enter and exit Russia legally.
Kreindlin said Russia's Federal Migration Service has agreed to issue transit visas if investigators approved.
"Now we, our lawyers, will negotiate and work with the Investigative Committee to do it as soon as possible," Kreindlin said as he waited outside a detention center to greet Greenpeace activists as they walked out.
A well-connected Russian lawyer, Genri Reznik, has said that it was likely not only that the foreigners would be allowed to leave Russia but that the charges against them would be dropped under an amnesty to mark the 20th anniversary of Russia's constitution on Dec. 12.
Australian Colin Russell was the first one to come before a judge when the bail hearings began in St. Petersburg courts on Monday and the only one to have bail denied. Greenpeace lawyers have appealed.
Russian photographer Denis Sinyakov, who was released Thursday, said he believed the decision to grant bail to the detainees came from the top and the judge hearing Russell's case hadn't got the signal in time.
All of the others were released on bail of 2 million rubles ($61,500).
In addition to Willcox, the 17 others freed from jail on Friday included six Britons: Anthony Perrett, Alexandra Harris, Iaian Rogers, Jonathan Bush, Frank Hewetson and freelance videographer Kieron Bryan. The others were Marco Weber of Switzerland, Mannes Ubels and Faiza Oulahsen of the Netherlands, Paul Ruzycki and Alexandre Paul of Canada, Jonathan Beauchamp of New Zealand, Miguel Hernan Perez Orsi of Argentina, Ruslan Yakushev of Ukraine, Gizem Akhan of Turkey and Russians Roman Dolgov and Dima Litvinov.
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Vitnija Saldava contributed to this report.