Tonga did seem to avoid the attentions of Europe for quite some time, despite the Dutch visiting in 1616 (though that was only to an out-island, the main island was visited by the Dutch for the first time in 1643) and Cook's visits in the 1770s. Missionaries turned up late in the 1790s and 1820s and in 1900 the islands became a British protectorate, but they do seem to been have left alone largely.
Now, an expansionist or at least exploring-minded China might make contact...
Now, an expansionist or at least exploring-minded China might make contact...