Rostyslav broke the junior national record in 100 m breaststroke in 2018.[4]
In 2019, Rostyslav represented Ukraine at the 2019 European Youth Summer Olympic Festival, held in Baku, where he won a gold medal in 100 m breaststroke and a silver one in 200 m breaststroke.[5] Also he competed in Multinations Youth Swimming Meet 2019, held in Graz, Austria,[6]
where he received two gold medals in 100 m breaststroke (the national junior record) and also in 200 m breaststroke.[7]
In 2020, he broke a national junior record in 50 m breaststroke at the Ukrainian National Swimming Championships in Dnipro.[8]
In the following years, he competed at the 2020 European Aquatics Championships in 50, 100 and 200 metres breaststroke without reaching a final.[9][10]
Also he competed at the 2021 European Junior Swimming Championships, where he won a silver medal in 50 m breaststroke and a bronze one in 4 × 100 m medley relay mixed.[11][12]
Then he represented Ukraine at the 2021 FINA World Swimming Championships (25 m) in 50 m breaststroke[13] without reaching a medal.[14]
