Byford Dolphin was a semi-submersible, column-stabilised drilling rig operated by Dolphin Drilling, a subsidiary of Fred Olsen Energy. Byford Dolphin was registered in Hamilton, Bermuda,[3] and drilled seasonally for various companies in the British, Danish, and Norwegian sectors of the North Sea. In 2019, Dolphin scrapped the rig.[5]

The rig was the site of several serious incidents, most notably an explosive decompression in 1983 that killed four divers and one dive tender, as well as critically injuring another dive tender.[6]