Mystic Sands is on the northern island of Vava'u, Tonga, about a one hour flight from the capital of Nuku'alofa which is on the main island of Tongatapu. There is also an inter-island ferry available for travel between Tongatapu and Vava'u. The trip takes 22 hours and the vessels are only suited to hardy sailors.

The Kingdom of Tonga comprises 4 main island groups: Tongatapu, Ha'apai, Vava'u & the Niuas. These run South to North, along the "Tonga Trench" close to the 180 meridian or International Dateline. Vava'u is well known as a paradise for marine activities, with its beautiful scattered group of tropical islands, beautiful beaches and friendly people. You can fly to Tonga, which is the main island of the Kingdom and your stepping stone to Vava'u.
See below for connecting Airlines.

International air travel
From New Zealand on Air New Zealand and Pacific Blue.
From Fiji on Air Pacific.
From Los Angeles on American Airlines to Fiji and then on Air Pacific to Tonga.
From Samoa on Polynesian Airlines.
From Australia on Air New Zealand, Air Pacific or Pacific Blue.

Domestic air travel within the Tonga group is provided by Chathams Pacific Airlines. You can book through their website.

More info if you need it is on the official Tonga Tourism website tongaholiday.com or phone us on +67 67 58 40 27 for help. Pacific Blue, part of the Virgin group, flies to Tongatapu twice weekly from Auckland, NZ and weekly from Sydney, Aus. They have great prices on one way or return fares.