Free-diving is a form of underwater diving in which divers hold their breath instead of using a breathing apparatus such as scuba gear.

An August 4 joint statement from Molchanova's family and AIDA International, the worldwide federation for breath-hold diving said: "Natalia Molchanova was recreationally free-diving off the coast of Spain on August 2, 2015 when she was separated from her peers.

She was diving without fins to around 30 to 40 meters (98 to 132 feet) and (supposedly) got into (a) strong underwater current.

"Search efforts have been ongoing during daylight hours and the next day since she was reported missing by three peers. She disappeared while diving approximately two miles (3.2 km) northwest of the port of La Savina at Poniente de es Freus."

Molchanova's family and peers appear to have accepted that she is presumed dead. Her son, 28-year-old Alexey Molchanov, also a champion free-diver with a total of 4 world records, told the New York Times: "It seems she'll stay in the sea. I think she would like that."

William Trubridge, another world champion  also seemed to doubt her chances of survival.