Having applied for membership back in June, 1995, Tonga ratified its accession package in June this year, finally completing the accession process, according to the WTO's Press Release.

According to Tonga Star, as part of its entry package, Tonga agreed to lower all import tariff lines to 15 or 20 percent within one year and was required to eliminate all industrial subsidy schemes prohibited by the WTO by the final date of its entry.
This was criticized by Oxfam, who warned that cutting tariffs would affect Tonga's ability to provide its essential services as the island kingdom earns some two thirds of its revenue from trade taxes.

Tonga joins fellow Pacific Island neighbors, Fiji, Papua New Guinea and the Solomon Islands.