Natalia Molchanova, 53, was diving for fun just off Formentera, an island near Ibiza, on Sunday when she failed to resurface from the water.
Search crews were despatched but so far no trace has been found of the champion free diver, who holds 41 world records for the sport.
Her family described how her passion for free diving ‘burned so deep inside of her that she dedicated her life to it.’
‘Natalia trained hard for her sport, she had a nine minute breath hold, could dvd to a depth of 101m using a fun and swim a distance of 234m with a fin’ her family said in a joint statement with freediving federation AIDA.
Molchanova is presumed dead, with experts fearing she may have been caught up in powerful ocean currents while diving.
This morning Will Trubridge, a 15 time world record holder in the same sport, said: ‘The world has lost its greatest free diver.’
‘I don’t think anybody would dispute that.’
Natalia holds the most records in the world for free diving.