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To Sua Ocean Trench

To Sua Ocean Trench

Coasts & CliffsSamoaAtua,Samoa
Fragile nature — stay on the trail, leave no trace.

A pool sunk thirty metres into a Samoan lava field, fed by seawater seeping through the rock and reached only down a tall wooden ladder.

September·Peaking now

May–Oct

Samoa's cool dry season: monthly rain drops below 150mm, the sea calms and the tunnel-fed pool runs clearest and most emerald. Air holds near 27°C and the sea around 27–28°C, the year's calmest, best swim.


Year-round The tide-fed emerald trench is a year-round swim; Samoa's drier months, May to October, bring the calmest, clearest water.

To Sua is a swimming hole sunk thirty metres into a lava field on the south coast of Upolu, the main island of Samoa, a round pool of clear green water at the bottom of a shaft of black rock hung with vines, fed by the sea through channels in the stone and reached only down a tall wooden ladder. The name means big hole, and it began as a dome, not a hole: a bubble in the old lava whose roof fell in, leaving a pit with gardens on the rim, ferns on the walls and the sea filtering in below. You back down the ladder bolted to the rim, rung by rung, thirty metres to a platform at the water, and swim out to the middle, where the pool is deep enough to float still with the circle of sky overhead and the walls green around you. On the shaded side a low rock opening marks where the hidden channels connect the trench to the ocean, and swimming toward it you feel a gentle surge, or see a small reef fish, proof that this calm-looking pool is the open sea coming in through the rock. The trench is what people come for, but the black lava field across the road is the other half of the site: the coast there is bare rock where the Pacific breaks, with blowholes throwing spray, tide pools and a rough beach, and the gardens around the rim are kept by the family that owns the land and charges the entry, as most of Samoa's sights are. The pool is swum in the morning before the day trippers arrive from Apia, and the light drops straight down the shaft around midday. To Sua sits on the coast road near Lotofaga, an hour from the capital, among villages of open-sided houses and churches. To Sua is a piece of the ocean at the bottom of a well, and the ladder is the only way to it.

Worth knowing

Good to know

  • Time your swim for high tide — the pool fills through sea tunnels, so it sits deepest and clearest when the tide is in; at low water it drops shallow and turns murkier.
  • The ladder is tall, steep and often slick — climb down facing the rungs and take it slowly; a floating platform waits at the bottom, and confident swimmers are most at ease here.
  • Come at opening or late afternoon — tour buses from Apia arrive mid-morning and the small pool fills quickly, so the early and late hours are by far the calmest.
  • Bring cash for the village gate — the trench sits on Lotofaga community land, and the family there collects a small entry fee that keeps the ladder and gardens maintained.
  • Cover up before walking back through Lotofaga — swimwear belongs at the water, and if a bell or conch sounds the evening Sa prayer, stop where you are until it ends.

Things to do

  1. 1

    Climb down the ladder into the trench

    Climb down the ladder into the trench

    Back down the tall wooden ladder bolted to the rim and drop rung by rung toward the water. Only from below do the walls, the ferns spilling over the edge and the sheer thirty-metre drop reveal their full scale.

  2. 2

    Swim out to the middle of the pool

    Swim out to the middle of the pool

    Kick out to the deepest part and lie back until the water holds you still. From here the walls rise sheer for thirty metres to a single ring of daylight, ferns and vines spilling over the far rim. A small floating platform at the foot of the ladder is where people haul out to catch their breath between swims.

  3. 3

    Find the passage where the sea flows in

    Find the passage where the sea flows in

    Swim to the shadowed side of the pool and trace the low rock opening where hidden channels connect the trench to the ocean. Here the water stirs and the daylight gives way to cool, echoing dark.

  4. 4

    Cross to the blowholes in the lava field

    The trench is what people come for, but the black lava field across the road is the other half of the site. Surf drives up through openings in the rock and falls back into shallow pools calm enough to sit in, and the shelf under them is the same drained tunnel system that hollowed out the trench behind you. Take the clifftop lawns on the way back: the decks there stand over open sea rather than over the pool.

Watch

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