South Twin is a granite pinnacle site in the Mergui Archipelago with gully formations, overhangs, and swim-throughs that make it more varied than a plain reef. It is usually run as a liveaboard dive with little current and clear water, so divers can move between boulders, fan-covered gaps, and sharky blue water without a heavy drift. The site works well for intermediate divers and rewards slow scanning for ribbon eels, nudibranchs, and reef sharks.