Five protesters waded ashore from high-speed launches after leaving the Greenpeace ship Arctic Sunrise, waving banners in the shape of a whale fin bearing the slogan "R.I.P."
A crowd of television cameras, met the protesters who were joined by five other Greenpeace activists already on the beach of the luxury resort hosting the International Whaling Commission's (IWC) annual meeting.
Wearing blue vests with the phrase "Defend Our Oceans", the protesters were restrained by police with plastic cuffs after staging a sit-in protest on the beach, before being led away.
St Kitts and Nevis police chief Robert Jeffers said the protesters would be charged with infringing immigration laws and obstructing a police officer.
"As far as we are aware, they have entered the federation without the consent of an immigration officer," he said.
A Greenpeace spokesman, John Bowler, said the protestors would be detained and would appear in court on Monday morning.
Greenpeace spokesman Mike Townsley was being held alone in a small cell, and could also face charges of resisting arrest, Mr Bowler said.
The protest came a day after Greenpeace earned a gentle rebuke at the IWC meetings over a collision between the Sunrise and a Japanese whaling vessel in the Southern Ocean in January.
A US intervention headed off a Japanese proposal which could have seen Greenpeace stripped of its observer status at the IWC's annual meetings.
The gathering has been dominated by a power grab by pro-whaling nations opposed to a two-decade-old moratorium on commercial whale hunts.
In the end, the IWC adopted a general resolution which did not assign blame for the incident or mention Greenpeace but did make clear that it did not "condone" dangerous protests at sea.
Each side blames the other for the January 8 incident in the Southern Ocean whale feeding grounds.