Nen Sothearoth played for Cambodia's under-21 team at the 2012 Hassanal Bolkiah Trophy, making his debut in a 2–1 loss to Vietnam.
On 17 August 2017, he scored a penalty goal after a Vietnamese player handled the ball in penalty box, the only goal that the Cambodian U-22 team scored during the 2017 Southeast Asian Games campaign.
Nen Sothearoth made his international debut in an unofficial friendly match against the Philippines in 2012.
He played in his first official matches for Cambodia three years later during qualification for the 2018 World Cup.
[3] Nen Sothearoth started playing for Svay Rieng in 2011, although he was part of a debated incident in a controversial match against Phnom Penh Crown as in minute 41 he appeared to clear the ball off the line with his hand.