French-Swiss yachtsman Laurent Bourgnon was reported missing while diving in French Polynesia on Wednesday. Bourgnon, 49, was on a private diving trip on his yacht off the atoll of Toau, 375 km north-east of Tahiti, reports RFI.
Four tourists and three crew members were also on the yacht.
Bourgnon went diving on his own on Wednesday, police said, while the four holidaymakers and the instructor had gone together.
The group reported some difficulties in reaching the surface although the area is not particularly dangerous.
The crew members, a cook and a hostess, had difficulty raising the alarm as Bourgnon was the only one who knew to operate the communications system.