Mariya Shubina took up several sports after World War II while studying and working as a gynecological medical specialist. She specialized in skiing and track athletics at first, and thus did not participate in canoeing until relatively late. In 1959, she won the first of the 10 national titles that she would capture across various disciplines and continued to collect them through 1967. He first international gold medal, however, had come a year earlier in the K-2 500 at the World Championships, with Nina Gruzintseva, while the duo also took silver in the European Championships in 1959. At the 1960 Rome Olympics, Shubina was partnered with Antonina Seredina, and again captured the title.
Shubina had her greatest successes at the 1963 World Championships, where she won the K-1 and K-4 500 races and took silver in the K-2 500. She did not attend the 1964 Tokyo Olympics, but took gold in the K-2 and K-4 500 at the Europeans in 1965. At the World Championships in 1966, she defended her gold in the K-1 500 and silver in the K-2 500, with her final major international medal, gold in the K-4 500, coming at the 1967 European Championships. By career she studied biology as it related to canoeing performance at the Volgograd State Academy of Physical Culture, and earned a PhD in 1975.