Oleg Kostin

Oleg Olegovich Kostin (; born 6 May 1992) is a Russian swimmer. He competed in the men's 50 metre butterfly event at the 2017 World Aquatics Championships. At the 2018 European Championships in Glasgow, he won a bronze in the 50 metre butterfly, setting a Russian 50 metre butterfly record of 22.97 seconds.

At the 2023 Russian National Championships, in April at the Palace of Water Sports in Kazan, Kostin set a new Russian record of 22.62 seconds in the 50 metre butterfly in a time trials conducted after the semifinals and before the final and contested by five of the swimmers in the event.