This is the incredible moment couples had underwater weddings on Valentine's Day in Thailand.

Twelve pairs of newlyweds - one Chinese, one Malaysian couple, one Indonesian couple, and nine Thai couples - plunged into the beautiful turquoise waters of the Andaman Sea to tie the knot in an annual group wedding ceremony in the southern province of Trang on February 14.

The grooms and brides still wearing their wedding veils and dresses donned scuba gear then dived off the Emerald Cave on Koh Kradan island.

Local officials performed a 'rod nam sang' or water pouring ritual symbolising purification and union before the couples received their marriage certificates underwater.

The wedding was overseen by Trang Governor Songklod Sawangwong.

A lively reception was held following the ceremony.