The Blick tabloid said Weber had arrived back in Zurich by train. It quoted Greenpeace as saying the activist had travelled from Helsinki via Copenhagen and Hamburg.
Earlier on Monday Greenpeace Switzerland sent out an invitation to a media conference with Weber to be held on Tuesday.
Weber and 14 Greenpeace protestors had received a Russian exit visa on Thursday following Russian lawmakers’ decision to approve a Kremlin-backed amnesty bill to end the prosecution of the activists.
A total of 30 people, including Weber who comes from Zurich, were arrested by Russian Special Forces on September 18th and charged with hooliganism after they mounted a Gazprom drilling platform in the Barents Sea in protest against Arctic oil drilling.
Last month, the entire crew was released on bail after Russia's Duma lower house of parliament voted 446 in favour to none against for the amnesty, which commemorates 20 years since Russia ratified its current constitution.
The bill, branded as a mere token gesture by rights activists, went into effect later on Wednesday and should also see several anti-Vladimir Putin protesters, jailed after a May 2012 rally, walk out of prison.
The amnesty affects a range of categories like mothers with dependents, minors and the elderly.
However, it also specifically mentions the charge of hooliganism as well as the charge of participating in mass riots.
The amendments meant that prosecution of the entire crew of the Greenpeace Arctic Sunrise ship would end and the 26 foreign protesters could finally go home.
Briton Anthony Perrett was the first of the activists to receive his exit visa on Thursday morning.
On Thursday, the charges against the final activist, Italian Cristian d’Alessandro, were finally dropped.
“The Arctic is still threatened by the greed of oil companies,” Weber was quoted as saying by Greenpeace following the news of his release.
“We will be able to rejoice only when the Arctic has been placed under protection.”
The organisation added that, despite the freeing of the activists, it would continue to fight for the protection of the Arctic.
News of the activists’ release comes one day after Kremlin critic Mikhail Khodorkovsky, who walked free from a Russian prison last week after a decade in jail, applied for a three-month Schengen visa to travel to Switzerland, according to Switzerland’s foreign ministry.