By Air
Fua'amotu International Airport (TBU) on Tongatapu is the main point of entry. It sits about 21km south of Nuku'alofa; taxis are available outside arrivals.
Fiji Airways operates regular flights from Nadi (Fiji), and is usually the easiest connection point from Australia, New Zealand, or the United States. Air New Zealand flies directly from Auckland. Flights from further afield typically route through Sydney, Auckland, or Nadi.
There are no international or domestic flights on Sundays — this is written into Tongan law.
Vava'u's Lupepau'u Airport (VAV) receives some international flights from Fiji, which lets you skip Tongatapu if Vava'u is your main destination.
Visas
Citizens of most Western countries, including the US, EU, UK, Australia, and New Zealand, can enter visa-free for up to 31 days. EU/Schengen passport holders may stay up to 90 days. You'll need a confirmed onward ticket and proof of funds. Extensions can be arranged through the Immigration Division in Nuku'alofa.
By Sea
Tonga has no regular international passenger ferry services. Cruise ships do call at Nuku'alofa and occasionally Neiafu (Vava'u). Yachts are welcome; the main ports of entry are Nuku'alofa, Neiafu, Pangai (Ha'apai), and Niuatoputapu. Yacht entry procedures require advance notice to customs.
Departure Tax
A departure tax is included in most airline tickets. Check your ticket — if it's not included, it is payable at the airport.