New Zealand activist David Haussmann has left a detention centre in Russia after being granted bail.
A second New Zealander, Jonathan Beauchamp, was granted bail on Thursday, but remains in custody.
He and Mr Haussmann are among 30 people facing hooliganism charges over the protest the protest at a drilling platform owned by Russian state oil company Gazprom.
Mr Haussmann's older brother Tony Haussmann said he received a message overnight on Thursday that his brother was being taken from the detention centre to a hotel for a debrief by Greenpeace.
"They haven't been givent their passports or visas back. We're still unsure whether they can actually travel to come home. It's still highly unlikely."
Greenpeace New Zealand said it will be at least two days before Mr Beauchamp is let out of the detention centre. A Greenpeace lawyer in Russia says neither man will be able to leave the country as they do not have the right visas to travel.
The activists were initially charged with piracy and faced up to 15 years in jail over the protest on 18 September.
Russian president Vladimir Putin said a week after the protest that the activists were clearly not pirates and investigators later changed the charge to hooliganism, which carries a maximum sentence of seven years.
UN appeals for leniency
United Nations Secretary-General Ban Ki-moon appealed to Russia on Thursday to show leniency towards the protesters.
In Warsaw, Mr Ban said groups such as Greenpeace had a role in shaping the world, not just governments and business.
"They (Russia) may have their own domestic rules and regulations but I would hope that they would have some favourable and sympathetic considerations for this case," he told Reuters.
By Thursday, courts in St Petersburg had granted 26 of the 30 bail and ruled that one, Australian Colin Russell, can be held until 24 February. The courts have set bail at two million roubles ($73,500).