Having previously represented Sierra Leone at under-20 level, Kamara made his senior debut for Sierra Leone against Liberia on 26 July 2018. He represented Sierra Leone at the 2019 WAFU Cup of Nations. He did not travel to Kono to play a friendly match in November 2019 after suffering a bereavement, but received a two match international ban from the Sierra Leone Football Association after it was discovered he played a community match in Freetown during this period.
Kamara was called up to Sierra Leone’s squad for the 2021 Africa Cup of Nations tournament, which began in January 2022. He scored his first international goal with a “magnificent left-footed strike” in a 2–2 draw with Ivory Coast in Sierra Leone’s second group match on 16 January 2022. He appeared in their third group match as they were eliminated from the competition after a 1–0 defeat to Equatorial Guinea.