Regional highlights
Khao yam (southern Thai rice salad)
The most distinctively southern Thai dish — a dry salad of steamed rice mixed at the table with a kaleidoscope of fresh and dried ingredients: toasted coconut, dried shrimp, thinly sliced kaffir lime leaves, pomelo segments, lemongrass, wing beans, bean sprouts and shredded green mango, dressed with a budu (fermented fish sauce) or a sweet-sour dressing of palm sugar, lime and fish sauce. Each component is served separately on a plate or in a banana leaf, assembled by the diner. Cooling, herbal and gently sour — a direct contrast to the richness of the island's coconut curries. Found at southern Thai cook shops in Nathon and at the Bophut morning market.
Massaman curry
The mildest and most aromatic of Thai curries, particularly strong in southern Thailand where the Muslim influence from the region's historical trading connections with Persia and the Indian subcontinent is most evident. Koh Samui's massaman is typically made with beef (slow-cooked until the connective tissue melts) or chicken, simmered in a coconut-milk sauce fragrant with cinnamon, cardamom, star anise, clove and nutmeg, with whole roasted peanuts and potato. The spice blend (reminiscent of biryani or a mild korma) reflects the curry's Muslim-Malay-Persian lineage. Served over jasmine rice; the sauce should be thick and richly fragrant rather than broth-like.
Tom yum goong
The essential Thai soup — a clear, sour-spicy broth of lemongrass, galangal, kaffir lime leaves, chilli and fish sauce with whole fresh prawns, finished with lime juice and fresh coriander. The Gulf of Thailand version uses the large gulf tiger prawns or the spotted prawns caught off Samui's east coast; the broth at local restaurants is made from scratch with whole prawn shells rather than the stock cubes common at tourist-facing venues. Served with steamed rice; the tom yum nam khon (coconut-milk version) is a milder, richer variant also widely available.
Grilled Gulf seafood
Koh Samui's most straightforward food pleasure: fresh fish (red snapper, barramundi, grouper), whole squid, tiger prawns and scallops grilled over charcoal at beach restaurants along Chaweng, Lamai and Fisherman's Village in Bophut. The fish is scored, marinated briefly in garlic-lemongrass paste and grilled until the skin crisps and chars; served with a fresh dipping sauce of lime, fish sauce, chilli and coriander. The quality is determined entirely by the freshness of the morning's catch — beach restaurants buying directly from the local fishing boats produce a noticeably superior result to those relying on wholesale suppliers.
Pad thai
Rice noodles stir-fried with egg, bean sprouts, dried shrimp, tofu and spring onion in a tamarind-fish sauce-palm sugar sauce, served with crushed peanuts, dried chilli and lime. The version at Koh Samui beach stalls is reliable and widely available; quality varies from the excellent (freshly soaked noodles, screaming wok heat) to the acceptable (pre-soaked noodles, lower heat). The prawn version (pad thai goong) is the most popular; the best versions are at the Nathon and Lamai night markets where Thai families eat alongside tourists.
Green curry (gaeng kiao wan)
The hottest and most aromatic of Thailand's three principal coconut curries — named for the fresh green chillies that dominate the paste, blended with lemongrass, galangal, kaffir lime zest, shrimp paste and fresh coriander root. Made with chicken, fish or prawns simmered in thick coconut milk with Thai aubergines (small, round and slightly bitter), bamboo shoots and fresh Thai basil. Green curry at a local Koh Samui cook shop is typically much spicier than the restaurant version — the tourist-menu version is adjusted to a lower heat level. Thai basil leaves wilted in at the end of cooking are the finish; removing them quickly preserves their fragrance.
Som tam (green papaya salad)
Pounded green papaya salad — shredded unripe papaya, chilli, garlic, green beans, tomato, dried shrimp and peanuts mortar-ground with a dressing of lime, fish sauce and palm sugar. The Koh Samui version follows the central Thai style (sweeter, with fish sauce rather than fermented crab), served as a starter or snack alongside grilled pork or sticky rice. The dish is made to order at every vendor's mortar — spice level is specified at the time of ordering. A ubiquitous, inexpensive and genuinely delicious Thai eating experience even at its most basic.
Mango sticky rice
Glutinous rice steamed in salted coconut milk, served alongside ripe sliced mango (Nam Dok Mai variety when in season), drizzled with sweetened thick coconut cream and topped with crisp mung beans or sesame. The key to quality is the ratio of sweetened coconut-milk in the rice versus the thickness of the topping sauce; the best versions come from dedicated dessert vendors at the Lamai and Chaweng night markets who make only this dish. Peak mango season is March–June; outside this period, lower-quality imported mangoes make the dessert significantly less rewarding.