4 curated Scuba Diving spots in Tonga, each with its own note and source.
Zentral · Best time: Jul–Oct · All levels
Arches, caves and seamounts: the Arch of Ofalanga starts at 20 metres and calls for Advanced, Hot Spring Cave with its thermal vent sits between 25 and 28 metres. The Bank drops from 6 to 28 metres and works for every certification level. Visibility in Tonga averages around 30 metres; Ha'apai is the only group offering dive courses.
Sources: Tonga Pocket Guide, Tonga Pocket Guide
Vava'u · Best time: May–Oct · All levels
An overhead dive at the northwest tip of Kapa: the cave mouth starts at about 4.5 metres, the floor of the main chamber sits near 18 metres, and a second entrance lies at roughly 12 metres. The opening faces west, so afternoons pay off. One part of the second cave carries very strong current — plan accordingly.
Sources: SV Soggy Paws – Tonga Dive Guide
Hauptinsel · Best time: Jul–Oct · Beginner
Diving happens on the outer reef with its coral-covered canyons, caves and drop-offs, plus Cathedral Cave off neighbouring 'Eua: a chamber some 100 metres across, entered at about 28 metres. Tongatapu caters to certified divers; no courses are run here. Visibility varies with the nutrient-rich currents; water 21 degrees in winter to 24 in summer.
Sources: Tonga Pocket Guide, Dive Adventures
Vava'u · Best time: Jul–Oct · All levels
Reef edges, chimneys, caves and swim-throughs, plus the Clan MacWilliam wreck: a 140-metre copra steamer that sank in 1927, sitting upright in Neiafu harbour and reaching close to 40 metres. Visibility tops 40 metres year-round, water 25 degrees in winter to 30 in summer; migrating humpbacks are audible underwater in winter.
Sources: Dive Tonga, Neiafu
Without a dedicated Scuba Diving note yet, listed on the country page: Pangaimotu.