Greenpeace activists have left two rigs on the North Sea due to safety concerns.
The environmental group said increasingly bad weather had forced it to take the climbers off the Brent Alpha and Bravo platforms.
Shell confirmed three protesters had occupied the two platforms from Monday morning.
Activists had been protesting against plans by the oil firm to leave parts of the rigs in the sea after decommissioning.
Greenpeace described the move as a “toxic time bomb” and said they would continue to watch the oil firms movements.
Shell described its plans as “safe” and “environmentally sound”.
A committee called OSPAR, made up of 15 governments, will examine the plans by Shell on Friday.