.TO is the country code domain for Tonga. It is operated by the registry TONIC and can be registered by anyone for a minimum two year period.

Tonic is the Tonga Network Information Center established on 1995, and have been the national DNS registration authority for the country of Tonga.
Registrants of names are sent email warning them that their name registration is about to expire. One month after expiration, names which have not been renewed are once again made available for registration on a first-come first-served basis.