The Boathouse, on the southern end of Kata Yai Beach, has been an institution since the 1980s — a colonial-style wooden restaurant on the sand with a wine list to match its prices. The cooking is Thai-French, the seafood is consistently good, and the wine cellar runs to several hundred labels.
Expect to pay 1,000–1,500 baht a head with drinks. Sunset reservations book out in high season. The attached cooking school does well-regarded half-day classes.