Red Onion is a long-running local favourite on the beach road in Karon, popular with both residents and returning visitors. The menu covers Thai standards — pad thai, green curry, tom yum soup, massaman, and grilled seafood — at prices well below what the resort-facing restaurants charge. The portions are generous and the quality consistent.
It's an open-air place, simple in decor, with plastic chairs and a menu on the wall. Exactly the kind of restaurant Karon needs more of: no pretension, good food, reasonable prices. The seafood dishes are particularly reliable, especially the grilled fish and the whole sea bass in chilli sauce.