To Sua Ocean Trench is a stunning attraction site featuring a unique land formation. It consists of two giant holes joined via an ancient lava tube cave, one without water and the other a beautiful 30m deep swimming hole with turquoise water accessed by a ladder. Nearby blowholes, lava fields, lush gardens, and tide pools await swimmers as a reward for braving this tropical thrill ride. To Sua is filled with seawater that is directly connected underground with the nearby ocean. It is the second-largest in the geographic area and the most populated of the Samoan Islands. The pool is fed through a cave that leads out to the ocean washing in refreshingly cool water.