Ten days across three of Tonga's four island groups — the stone tombs and trilithon on Tongatapu, the rainforest and cliffs of 'Eua, and humpback mothers and calves in Vava'u. Every leg is a small domestic aircraft or a boat, one whole day is a Sunday on which nothing legally moves, and the route is built around both of those facts rather than pretending either can be worked around.
Nuku'alofa
A capital of perhaps twenty-five thousand people that you can walk end to end in an hour. The Royal Palace on the waterfront is white timber, prefabricated in New Zealand and shipped in 1867, and you look at it over the fence — it is a residence, not a museum. Malae Kula, the royal burial ground, is a walled field of graves a few streets inland. Talamahu market is the place to work out what the country actually eats: taro, yam, kava root, coconuts sold by the sack. The waterfront road is also where the January 2022 tsunami came ashore, and much of the commercial centre behind it is post-2006 reconstruction after the riots of 16 November that year burned most of the old one down.
Eastern Tongatapu
Hire a car for the day — the buses radiate from Nuku'alofa and will not do a loop. Ha'amonga 'a Maui stands in scrub at Niuto'ua: two coral-limestone uprights with a mortised lintel laid across them, raised under Tu'itatui around AD 1200 and weighing several tonnes a piece, with the king's backrest stone in the clearing behind. At Lapaha, the old capital of the Tu'i Tonga, the langi are stepped tombs faced in cut coral slabs — Paepae 'o Tele'a is the one to stand in front of, and the scale of the quarrying and hauling is the point. Anahulu cave at Haveluliku has a freshwater pool you can swim in by torchlight; it is on family land, so you pay at the gate and someone walks you down.
The south and west coasts
Mapu'a 'a Vaea at Houma is a five-kilometre terrace of coral rock the swell forces water through, firing spray twenty metres up in a line of vents; it is best in a southerly and worth an hour rather than ten minutes. Hufangalupe, back east along the south coast, is a natural land bridge over a cove with no easy way down to it. At Kolovai, a colony of Pacific flying foxes hangs in the casuarina trees beside the road in daylight — traditionally tapu and treated as belonging to the monarch, which is why they are still there. Finish at Ha'atafu on the western tip, near the marker for Abel Tasman, who anchored off this coast in January 1643 and traded for water and pigs.
Sunday
Written into the route deliberately: set your arrival so that this day is the Sabbath, because it will be a fixed point whether you plan for it or not. With ten days that means landing on a Thursday, which is also what keeps the last day — the one that depends on a domestic flight — off the Sabbath. Clause 6 of the 1875 constitution holds that no person shall practise a trade or conduct any commercial undertaking on the Sabbath, and it is enforced: shops shut, domestic flights and ferries do not run, restaurants outside hotels close, and some villages take a dim view of swimming. Go to church. The Free Wesleyan Centenary Chapel in Nuku'alofa is where the royal family attends and the singing is unaccompanied, loud and in four parts; visitors are welcome with shoulders and knees covered. Afterwards is the umu, the earth oven, and if you are staying in a guesthouse you will probably be fed from one.
Across to 'Eua
The ferry leaves Queen Salote Wharf around the middle of the day and takes about two and a half hours across the Piha Passage, which is regularly rough enough that people who never get seasick do. The alternative is the Lulutai flight, which is eight minutes in the air and one of the shortest scheduled services anywhere. 'Eua is about eighty-seven square kilometres, rises to just over three hundred metres, and is around forty million years old — far older than the volcanic islands to the west, because it sits on the ridge rather than the arc. 'Ohonua is the landing and most of the accommodation is a guesthouse with a pick-up truck.
'Eua National Park
A full day on foot with a guide, because the tracks are unsigned and the sinkholes are not fenced. The park protects the largest remaining tract of rainforest in Tonga, with red shining-parrots in the canopy — the koki, introduced from Fiji long enough ago that Tonga now holds the more secure population. The eastern rim is a line of cliffs well over a hundred metres straight into the sea: Lokupo lookout above the forest, 'Anokula on the clifftop, and between July and October you sit up there and watch humpbacks working north below you without paying anybody for the privilege. Matalanga 'a Maui is a vertical sinkhole you climb down into on roots.
North to Vava'u
The eight-minute flight back to Fua'amotu, then the Lulutai service north to Vava'u, about an hour and a quarter over the Ha'apai group. Neiafu sits at the head of the Port of Refuge, one of the deepest and best-sheltered natural harbours in the Pacific — the Spanish navigator Francisco Mourelle reached it in 1781 and gave it the name it still carries in translation. The town is a single street above the water, the yacht fleet is at anchor below it, and most of the country's licensed whale operators work from this harbour — the rest are spread across Ha'apai, 'Eua and Tongatapu. Confirm your swim booking in person on arrival.
The whale grounds
Out at seven, back in the late afternoon, and most of the day is spent looking rather than swimming. The rules are the reason it works: one licensed boat with a whale at a time, four swimmers and a guide in the water, no touching, no getting between a mother and her calf, and the guide decides when everybody comes out. A calf born in this water in August has to put on enough weight on milk to swim to the Southern Ocean by November, and every minute of disturbance is taken off that. Some days you get three swims. Some days the wind is up and you get none, which is what the second whale day later in the week is for.
Kapa, the caves and Port Maurelle
A boat day through the inner islands. Swallows Cave on Kapa is a sea cave you motor into, with the light coming up through the water underneath; Mariner's Cave on Nuapapu is entered by diving through a submerged opening about two metres down and surfacing inside, which is straightforward for a confident swimmer and genuinely not for anybody else. It is named for William Mariner, the fifteen-year-old English boy who survived the taking of the privateer Port au Prince at Lifuka in 1806, lived four years in Tonga under the protection of Finau 'Ulukalala, and whose account, published in London in 1817, remains one of the best written records of the pre-Christian kingdom. Lunch at Port Maurelle, which is the anchorage Mourelle used.
Spare whale day, then south
Keep this day empty and use it for whatever the week took away — a second swim if the first was blown out, or the Mount Talau walk above Neiafu, an hour up through the bush to a flat summit with the whole Port of Refuge below it. The afternoon Lulutai service goes back to Tongatapu. Do not connect it to an international departure the same day: the domestic fleet is small, cancellations are ordinary rather than exceptional, and a night in Nuku'alofa is a great deal cheaper than a missed flight to Auckland.
Good to know
Most nationalities — EU and EEA, UK, US, Canada, Australia, New Zealand — are issued a visitor visa on arrival at Fua'amotu for 31 days, extendable in country, against a passport valid six months, an onward ticket and an address. A yellow fever certificate is demanded only if you are arriving from a country with transmission risk. The currency is the Tongan pa'anga and it is a cash economy outside the hotels: there are ATMs in Nuku'alofa and in Neiafu and effectively nowhere else, so draw what you need for 'Eua before you get on the ferry, and expect card payments to fail or attract a surcharge. Sunday is the single biggest planning constraint in the country and it is constitutional rather than customary — Clause 6 of the 1875 constitution prohibits trade on the Sabbath, so no domestic flight, no ferry, no shop and almost no restaurant operates, and an itinerary that ignores it loses a day at the worst possible moment. It governs the day you leave as much as the days in the middle: if your international departure falls on a Sunday, nothing domestic will move you to Tongatapu that morning, so be on the main island by Saturday night whatever the outbound ticket says. Whale swims run roughly July to October, are restricted to operators holding a licence, and cap the water at four swimmers plus a guide; August and September book out months ahead in Vava'u and are the two months when mothers with new calves are in the sheltered water. Book two swim days rather than one, because a day can be lost to wind outright and there is no refunding the weather. The domestic carrier is Lulutai Airlines, with a small fleet flying Tongatapu–'Eua–Ha'apai–Vava'u a few days a week: assume at least one leg will move, never plan a same-day connection onto an international departure, and treat the published timetable as an intention. The inter-island ferry to Ha'apai and Vava'u sails roughly weekly and takes upwards of twenty hours from Nuku'alofa — cheap, slow and not a schedule you can build around. Cyclone season runs from November to April and is also the wet, hot half of the year; June to October is dry, cooler and the whale season, which is why it is also when everything costs more. Driving is on the left and you must buy a temporary Tongan licence on arrival, taking your national licence and an international permit; the real hazard is pigs, which are on every road at every hour and are the commonest collision in the country. Dress matters: shoulders and knees covered in villages and any church, swimwear on the beach and not on the way to it, and a wrap for women is the simplest solution. Tonga's internet arrives on a single undersea cable, cut by a ship's anchor in 2019 and destroyed by the Hunga Tonga eruption in January 2022, which took the country offline for weeks each time — download maps and booking confirmations before you fly. Know the tsunami evacuation route from wherever you sleep on the coast; the 2022 wave came ashore in Nuku'alofa and the outer islands with very little warning.
Shorter or longer?
Four more days in the middle group, flying Tongatapu–Lifuka and on to Vava'u rather than direct. Low sand islands, almost no infrastructure, a handful of guesthouses on Foa, and the quietest water in the kingdom — Cook had already named Tonga the Friendly Islands on his 1773 visit and spent several weeks off Lifuka in 1777, and the Bounty mutiny happened off Tofua, visible on the western horizon, in April 1789. The trade is that you are now depending on two extra Lulutai legs.
Three days on Tongatapu and four in Vava'u, dropping 'Eua and the ferry. Keeps the tombs, the blowholes and both whale days; loses the rainforest, the cliffs and the only part of the route where you walk all day.