He competed at the 2012 Summer Olympics representing Sri Lanka in the men's 10 metre air rifle and men's 50 metre rifle prone which was also his maiden Olympic appearance. He failed to advance in both. Samarakoon also represented Sri Lanka at the 2016 Summer Olympics which was held in Rio de Janeiro. During the 2016 Summer Olympics, he blamed the Sri Lanka Shooting Sports Federation for failing to provide him a suitable shooting kit which made his participation quite difficult when he was slotted to compete in the men's 10m air rifle event. He was settled only for 50th position in the men's 10m air rifle event during the Rio Olympics.