After leaving Colchester he spent three years in
Singapore as player coach and then player manager for Woodlands Wellington. While in Singapore Clark obtained the Asian Federation A licence as a coach, following up by obtaining the English FA, UEFA A qualification on his return to Europe. Simon returned to the UK in 2005 and joined
King's Lynn as a player His first game in charge saw a 3–0 home victory over
Darlington on 5 September 2009 but was followed by three defeats against league leaders Bournemouth, Notts County and Shrewsbury Town.
Chris Sutton replaced him as manager on 28 September 2009. Clark took the 3–0 home defeat to
Notts County on the following day before leaving the club by mutual consent. Clark was sacked in September 2018 due to 1 win in 6. On 6 March 2019, Clark was appointed as Lead Youth Development Phase coach for
Northampton Town. In this position, he was going to oversee the development of players in the Northampton Town Academy from the age of 13 to 16. ==Honours==