Om Ganesh
Om Ganesh has been a Haad Rin fixture for long enough that plenty of long-term residents treat it as their default "I need a proper curry" spot, not just a tourist stop near the pier. It's North Indian food β naan, thalis, the usual curry lineup β done properly rather than watered down for a beach crowd.
The upstairs seating is half the appeal. It's open-sided, looking down over the Haad Rin street scene, which makes it a genuinely good people-watching spot while you eat β especially useful on Full Moon Party nights when the street below turns into a costume parade. Get there hungry: there's a set/all-you-can-eat option that a lot of people say is the best value in town if you've got an appetite.
The recurring comment from people who've eaten here more than once is consistency β it's not the flashiest room in Haad Rin, but the food is reliably good trip after trip, which after enough disappointing tourist-town restaurants starts to matter more than atmosphere.