Krūmiņš was included into the senior USSR national basketball team in 1955. He was a dominant center for the Soviet Union at the 1956 Summer Olympics, and he helped the Soviet national team to reach the tournament's finals, and earn a silver medal. He played with the senior Soviet national team for about 10 years, and with them he won EuroBasket gold medals in 1959, 1961, and 1963; and Summer Olympic Games silver medals in 1956, 1960, and 1964. He also played at the 1959 FIBA World Championship.