The governing body of rowing says para-rower Dzmitry Ryshkevich died after his boat capsized during training at the world championships in Austria.
World Rowing cites a police statement that the flotation device on the 33-year-old Belarus athlete's boat had broken.
Although Ryshkevich freed himself from the safety belts in the boat, he sank into the water near the Danube in Linz-Ottensheim on Wednesday as rescuers approached.
Police say Ryshkevich's body was recovered from the murky, 8-foot-deep water more than two hours later. Police say reasons for the broken equipment "are yet unknown and are currently under investigation.''
Ryshkevich was competing at his third world championships. The races are qualifying events for the 2020 Tokyo Olympics and Paralympics.
International Paralympic Committee president Andrew Parsons said the incident is a "terrible tragedy.''