Adam Warner won bronze at the 10K at the Olympic venue at Eton Dorney Lake.
Competing in his first open water competition of the year, Warner completed five laps of a 2K circuit in 2:03, knocking 15 minutes off his personal best.
Warner said: “My open water season couldn’t have started on a more positive note. Having completed my pool schedule last week, I’m delighted to finish in the top three of a 10k swim, finishing with a very fast time. The season can only get better now.”
Warner’s next race is at the British Gas Great East Swim in Ipswich on June 16, where he will line up in the Elite field.