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To-Sua Ocean Trench
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The To-Sua Ocean Trench is a globally recognized geological wonder located in Lotofaga village on the southern coast of Upolu. This massive, circular sinkhole was formed by the collapse of an ancient lava tube, and it is linked to the Pacific Ocean via an underwater tunnel. The name 'To-Sua' translates simply to 'giant hole' in the Samoan language. The trench is approximately 30 metres deep, with the bottom filled with crystal-clear, turquoise seawater that rises and falls with the oceanic tides. Its near-vertical walls are draped in animated tropical greenery and hanging ferns, providing a remarkable natural contrast. Access to the water is provided via a steep wooden ladder leading to a diving platform. The site is set within beautifully landscaped botanical gardens and is adjacent to rugged volcanic cliffs that offer panoramic views of the powerful surf and blowholes along the coastline.
- Location: Samoa
- Top sights: Saleilua Church of Jesus Christ & the Latter-Day Saints · Saleilua Congregational Christian Church · Poutasi Congregational Christian Church
- Nearby: Siumu Tai (8 km)
Best time to visit & climate
The most pleasant time to visit is Jul–Sep.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg °C | 28 | 28 | 28 | 28 | 28 | 28 | 27 | 27 | 27 | 28 | 28 | 28 |
| Rain mm | 269 | 247 | 175 | 181 | 135 | 88 | 78 | 57 | 91 | 146 | 224 | 240 |
📋 Practical info
Best season
The To-Sua Ocean Trench is accessible year-round, but the best time to visit is during the dry season from May to October. The water is clearer and currents are weaker, making it easier to spot fish and sea turtles.
Best time of day
Early morning features soft light and usually calm water, good for beginner snorkelers. Late afternoon often brings more fish activity as the sun lowers.
Etiquette
Do not touch coral or rocks, as they are fragile ecosystems. Feeding fish is prohibited, and loud noises should be avoided to prevent disturbing wildlife.
What to bring
Snorkeling gear (mask, snorkel, fins) is essential to explore the underwater world. Waterproof sunscreen and a life jacket for weaker swimmers are recommended.
Getting there
The To-Sua Ocean Trench is on the south coast of Upolu, about 40 minutes from Apia. Entry is via a small visitor center, from which a staircase descends to the pool.
What to expect
Fish and turtles are accustomed to visitors but won't appear instantly - stay still in the water and wait a few minutes. You'll get the best views by moving slowly and not stirring up sediment.
Geography
Facts
- The trench reaches a depth of approximately 30 metres.
- The water is saline and connected to the ocean via an underwater cavern.
- It was formed by the ceiling collapse of a massive prehistoric lava tube.
- A long, vertical wooden ladder provides the only access to the swimming area.
- The site is managed as a community tourism project by Lotofaga village.
- The surrounding area features scenic volcanic arches and active blowholes.
Explore nearby
Notable places around
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Sights in the town To-Sua Ocean Trench (3)
Poutasi Congregational Christian Church
Sights nearby
Frequently asked questions
How deep is the water at To-Sua?
The pool is about 30 meters deep, but swimming is safe if you are cautious.
Is To-Sua suitable for children?
Yes, but only with life jackets and under strict supervision as the ladder is steep.
When is the best time to visit?
In the morning it is less crowded and the light is handy for photography.
Is there an entrance fee?
Yes, there is a small fee for access to the park grounds for maintenance.
Are there restrooms?
Yes, basic restrooms and changing facilities are available near the entrance.
To-Sua Ocean Trench: where is it located?
To-Sua Ocean Trench is located in Samoa.
To-Sua Ocean Trench: what is there to see?
Highlights include Saleilua Church of Jesus Christ & the Latter-Day Saints, Saleilua Congregational Christian Church, Poutasi Congregational Christian Church.
To-Sua Ocean Trench: when is the best time to visit?
The most pleasant time to visit is Jul, Sep.
To-Sua Ocean Trench: why is it worth visiting?
The To-Sua Ocean Trench is a globally recognized geological wonder located in Lotofaga village on the southern coast of Upolu.
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