As a competitive swimmer, Marina Koshevaya had one great year: 1976. Although only 16-years-old, she won her only Soviet title, in the 100 breaststroke, and was selected to the 1976 Soviet Olympic team. At the Olympics Koshevaya surprised the world by winning the 200 breaststroke with a world record of 2:33.35, nearly three seconds ahead of compatriots Maryna Yurchenia and Lyubov Rusanova. This was also the first medal sweep by Soviet swimmers at the Olympic Games. Three days later Koshevaya won bronze in the 100 breaststroke. Koshevaya also competed at the 1978 World Championships, but did not make the finals of the 100 breast. In addition to her 1976 Soviet title, Koshevaya also won two silver medals (1976 in 200 breaststroke, 1978 in 100 breaststroke) and bronze thrice (1977 in 100/200 breaststroke and 1978 in the 200 breaststroke).
Personal Best: 100 m breaststroke – 1:13.20 (1976); 200 m breaststroke – 2:33.35 (1976).