Surat Thani is one of the better places in Thailand to eat Southern Thai food, which is spicier and often sourer than central Thai cooking. The city's position on the Gulf coast and its access to rivers and estuaries means fresh seafood is abundant and cheap.
Look for gaeng tai pla (a pungent fermented fish curry, an acquired taste but a Southern Thai staple), massaman (which originated in the Muslim south), and crab curries at the seafood restaurants along the river road. The night markets — particularly the large one near the bus terminal — are the easiest and cheapest place to eat well.