The conservation group says its members have been denied permission to leave despite a court ruling they should be allowed home.
Russian authorities have told 30 people arrested over an oil-drilling protest they cannot leave the country, according to Greenpeace.
The environmental group said the decision defied a ruling from an international court, which last month ordered Russia to allow the so-called Arctic 30 to travel.
Greenpeace also repeated its demand that the 28 activists and two journalists, including six Britons, should be allowed home. It denies any wrongdoing.
They have all been granted bail by courts in St Petersburg but remain in Russia while efforts are made to secure permission to leave.
In November, the International Tribunal for the Law of the Sea ruled that the activists should be allowed to leave immediately and the ship released, provided a bond of €3.6m (£3m) was posted.
The Netherlands - where the Arctic Sunrise is registered - paid the sum on November 29, meaning Russia is now in breach of the court order, according to Greenpeace.
It said Russia's Investigative Committee has written to one of the 30 - Anne Mie Jensen from Denmark - indicating she is not free to leave the country.
The organisation's lawyers said they expect all of the non-Russian defendants will be treated in the same way by the authorities, meaning they would now be forced to stay in St Petersburg for Christmas and beyond.
Peter Willcox, the American-born captain of the Arctic Sunrise, said: "I am ready to go home to my family.
"We were seized in international waters and brought to Russia against our will, then charged with a crime we didn't commit and kept in jail for two months.
"A respected international court says we should be allowed to go home, so do numerous presidents and prime ministers, but we can't get visas to leave the country.
"Even if we could, there's no guarantee the investigative committee won't schedule an interview for the day I get home, forcing me to break my bail conditions."
The foreigners could not be granted exit visas because their passports do not have Russian entry stamps, the Investigative Committee said.
:: Watch Sky News live on television, on Sky channel 501, Virgin Media channel 602, Freeview channel 82 and Freesat channel 202.