By 1200 GMT Greenpeace said it knew of the dropping of charges against 19 of the group, who are currently still in Russia on bail. The move followed the announcement of a Kremlin amnesty.
The activists will now be free to leave Russia and travel home to their families, once they secure exit visas.
Russia's treatment of the activists - who spent two months in detention and had faced hooliganism charges punishable by seven years in jail - had drawn heavy criticism from Western nations and celebrities.
Their amnesty will remove an irritant in relations in what Kremlin critics say is a move timed to improve Russia's image ahead of the Sochi Olympics.
"This is the day we've been waiting for since our ship was boarded by armed commandos almost three months ago," Peter Willcox, who captained the Greenpeace vessel used in the protest, the Arctic Sunrise, said in a statement.
"I'm pleased and relieved the charges have been dropped, but we should not have been charged at all."
President Vladimir Putin has said Russia's response to a Greenpeace protest should serve as a lesson and Moscow would toughen steps to guard against interference in its development of the region.
Russia says activists endangered lives and property in the protest at the state-controlled energy giant Gazprom's Prirazlomnaya platform in the Pechora Sea, a key element of Russia's plans to develop the Arctic.
Greenpeace said the boarding of its icebreaker by Russian authorities was illegal and denied says its activists conducted a peaceful protest.