The Tonga Island Marine Reserve, established in 1993, protects a 1,800-hectare stretch of coast and seabed between Awaroa and Bark Bay. The headline draw is the New Zealand fur seal colony on Tonga Island itself — easily approached by kayak or guided boat, with pups (born November–January) playing in the shallows around the rocks for most of the summer.
The reserve is the standard half-day kayak trip from Bark Bay or Onetahuti. No fishing is permitted; the difference in fish life inside the reserve versus outside is immediately obvious to snorkellers. Visibility is best in the calmer months of February and March.