A sea cave on the western coast of Vava'u accessible by boat, kayak, or swimming from a moored vessel. The entrance is a low arch at the waterline that opens into a large cavern rising 30 metres, lit from above by a natural skylight that floods the interior with shafts of filtered sunlight. The cave is large enough for a small boat to enter in calm conditions.
The cave is named for the Pacific swiftlets (a type of swift) that nest in their hundreds on the cave walls; the noise of their calls reverberates off the limestone. Snorkelling is excellent inside and around the cave entrance — the water is gin-clear. Most whale-watching and day-trip boats include Swallows Cave in their itinerary. It can also be reached by kayak from the main island in a day's paddle, though conditions need to be calm.