Belgian Musimu, 40, was found in the family pool last Thursday.
A post mortem result has yet to be reported and it is not clear whether Musimu succumbed to any form of voluntary apnea or to some other cause. He would relax in the pool after general workouts.
Musimu’s 209m No Limits plunge, where the diver descends on a sled and returns to the surface aided by a balloon, stunned the freediving world because it exceeded by nearly 40m the previous best.
The dive was not recognised officially by the sport’s governing body AIDA as Musimu dived outside its auspice, but few questioned its authenticity.
He dived to such depth by breaking new ground technically. Instead of equalising his middle ears and sinuses in a conventional manner, he developed a way in which to flood them with seawater so that he would not need to equalise at all.
This allowed him to dive deeper than had been possible before and, since his 209m dive, other freedivers have adopted the technique.
Today’s No Limits record of 214m was set by Austrian Herbert Nitsch in 2007.
Musimu’s last major public freedive was a No Limits tandem dive with Brazilian Karol Meyer to 121m off Bonaire in May last year, which was claimed as a record.
Musimu leaves a wife and young daughter.