Zirk, swimming for Estonia, claimed his podium place in the men’s 50m butterfly event.
He clocked 24.02 seconds to finish behind Ukraine’s Andrii Khloptssov and Spain’s Mateos Alberto Lozano.
Zirk’s Plymouth Leander team-mate Tom Fannon, competing for Great Britain, was unable to qualify from the heats with a 25.41 swim in the morning.
Meanwhile, Leander’s Laura Stephens eased through the heats and prelims to reach the final of the women’s 200m butterfly.
Stephens will go into Thursday’s final third fastest having clocked 2:10.99 in the semis. Her Great Britain team-mate Emily Large was quickest with 2:10.40.