Scuba diving in Tonga is excellent in all island groups with a beautiful environment in which to dive with year round warm sea temperatures dipping to 23 degrees Celsius in winter (May to Oct) and perhaps five degrees warmer in summer with only a thin wet suit required for diving. Visibility is generally very good at between 20 and 40 metres depending on the weather conditions, with greater clarity in the summer months of November to April so long as a storm isn't nearby which naturally spoils things The strong tradewinds which blow from May to October lessens visibility and makes the sea more choppy to travel in although during these months the humpback whales are in Tonga which are a bid draw for divers.
There area great many good coral reefs, drop-offs and passages which are easily accessible via protected lagoons and channels with dive boats seldom having to venture far into the open ocean and boat journeys from the operators base seldom taking more than 40 minutes. The main drawback is a lack of facilities for scuba divers with no decompression chamber (the closest is in Suva, Fiji), only a handful of dive operators offering daily trips and no live aboard charters for exploring the more remote coral reefs in the group.
Apart from stunning colonies of hard and soft corals and large pelagics, most impressive being the humpback whales, Tonga is renowned for its great variety of fire corals, nudibrachs and also for exceptional cave diving.
Scuba Diving in Tongatapu & Eua Island
The main island of Tongatapu has good protected reefs for exploring which are ideal for casual divers and those learning to dive on accredited PADI Courses. Advanced divers will enjoy some excellent passages full of fish as well as some good drift dives and drop-offs along the reef walls. The most exciting dives are off the volcanic island of Eua a few kilometres south of the lagoon which has underwater mountains with sheer drops and some exceptional caves to explore.
Scuba Diving in Ha'apai Group
Ha'apai offers a very diverse environment for scuba diving and suits both beginners and advanced divers with plenty of coral reefs to explore. Some of its more unique features are an underwater sea arch full of lobsters and crabs, a giant overhang where reef sharks like to hang out and the anchor of the pirate ship Port au Prince lying at a depth of just 18 metres and surrounded by bommies. Its also a more serene place to dive with humpback whales away from the bustle of Vava'u.
Scuba Diving in Vava'u
Vava'u has a very accommodation diving environment with a great mix of coral and limestone islands providing both exceptional reefs boasting giant sea fans, interesting caves as well as sheltered passages where you can scuba dive close to humpback whales. The season for visiting whales lasts from July to the end of October and during this time Vava'u's waters are a buzz with sightseeing tours and dive operators seeking out the whales. Although boat activity is nowhere near as boisterous as in most other parts of the world, for some it may appear that the whales are being unnecessarily stalked. Most dive operators are based at Neiafu Town which lies in the heart of the group although some of the best dive sites are in the southern section of Vava'u..