A teenage Lionel Lewis was touted by former Singapore coach Vincent Subramaniam as a future international, and the lanky keeper fulfilled those expectations with his progression into the senior squad. Lewis, who has a huge following, made his senior debut for the Singapore national team in a 2–0 friendly win over the Maldives on 9 April 2002. However, he only managed to grab the "No. 18" jersey from fellow keeper Hassan Sunny in 2004 and since then, he has regularly kept goal for the country in international tournaments.