The 27-year-old central defender has signed on a free transfer from League Two Bradford City following manager Peter Taylor's decision to strip him of his captaincy for criticising his team selection on a live radio show.
Rehman, a Pakistan international, became the first South Asian to play in the English top flight when he made his debut for Fulham, for whom he made 30 appearances. He has also played for Blackpool, Brighton and Hove Albion, Queens Park Rangers and Norwich City.
"This move is a good opportunity for him because we couldn't guarantee him a starting place," Taylor told the club's website.
"We wish him all the best at Muang Thong, he is welcome back any time."
Muang Thong United is Thailand's richest club, owned mostly by a local media company and boasting a new stadium with a capacity of 25,000. They won the Thailand Premier League (TPL) title in 2009 in its first season in the top flight.
The TPL, created in 1996, has undergone a major revamp in the last two years following pressure from the Asian Football Confederation to commercialise the league and raise playing standards. Most clubs are now owned by big local companies.
