Anahulu Cave

Under the coral limestone of eastern Tongatapu, Anahulu opens its chambers to the island's favourite underground ritual: steps descend past stalactites - lit enough to navigate, dim enough to keep the mystery - to a freshwater pool whose clear, cool water has hosted swimmers since the royal picnic era a century ago. The swim is the point: floating in the mineral-still pool while stalactites drip their slow millimetres overhead and local kids demonstrate leaps from ledges polished by generations. The beach outside adds a lagoon rinse, and the east-coast circuit - trilithon, blowholes at the far shore, Cook's landing - folds it into a natural day.

What you actually see

• The underground pool - the cool freshwater swim beneath the stalactites.
• The lit chambers - formations on the stair descent.
• The leaping ledges - local artistry from the polished rocks.
• Haveluliku beach - the lagoon shore outside the mouth.

When to go

Year round - the pool holds its temperature; weekday mornings are quietest, weekends add village life and swimmers. Bring what you need; the site is simply kept.

Honest expectations

Steps and cave floors are wet-slick everywhere - reef shoes or grippy sandals pay their way, and the lighting is functional, not theatrical. The pool is deep in parts with no lifeguards; leap only where locals show the depth. Facilities are basic changing huts.

Nearby

Ha'amonga 'a Maui, the east-coast beaches and Nuku'alofa.