A widepread search operation was launched after the Super-Puma aircraft went down 120 miles east of Aberdeen. ALl 20 on board were rescued.
It is believed the helicopter was approaching an oil installation when the accident happened.
ASea King helicopter from RAF Lossiemouth and a Nimrod jet from RAF Kinloss swept area but poor visibility hampered the search.
Helicopters from neighbouring platforms also joined in the operation.
The four-blade twin engine Super Puma is used frequently to take workers form the mainland to North Sea oil rigs.
A Super Puma helicopter, similar to the one involved in the incident
A British helicopter with eighteen people on board ditched in the water while approaching an oil installation in the North Sea on Wednesday. According to Her Majesty's Coastguard, everyone on board the aircraft survived the crash, and have been picked up by two life-boats.

The helicopter, a Super Puma registered (G-REDU) to Bond Offshore Helicopters, crashed about 125 miles miles east of the Scottish city of Aberdeen. A Nimrod jet from the RAF Kinloss, a Sea King helicopter from RAF Lossiemouth, and several choppers from nearby oil platforms searched the area after the alarm was raised at 18.40 GMT. The search effort, however, was hampered by limited visibility and low clouds in the area.

Dave Webster, a squadron leader with the Royal Air Force, said that this type of accident is a very rare occurrence.

The helicopter that ditched would have been equipped with survival suits to shield the passengers from the cold waters, as well as a flotation device.