On 1 September 2014, Keimuine got his first national callup after he was named in Namibia's 23-man squad by coach Ricardo Mannetti, for a friendly against Swaziland. The game ended in a 1–1 draw. In May 2015, Keimuine was part of the Namibian squad which won the 2015 COSAFA Cup. On 21 June 2016, he scored his first ever international goal in a 3–0 win against Mozambique in the 2016 COSAFA Cup. On 3 January 2019, he was named in Namibia's 23-man squad for the 2018 CHAN finals in Morocco. Namibia defeated Ivory Coast, Uganda and drew against Zambia to finish second in the group behind Zambia, and qualified for the next round. They were knocked out of the tournament in the quarter-finals by hosts and eventual champions Morocco.