Fly By is a north Koh Tang drift reef for divers who want current, structure, and a moving reef line rather than a static swim. The route runs over rocky seabed with coral bommies near the shallower edge and more relief farther out. Boat timing matters because the best dive is the one the operator can drop and pick up cleanly. When conditions line up, the reef holds dense fish traffic and a fast-moving, open-water feel.