Celebrations are expected to continue into the night after the Crown Prince of Tonga married his cousin in the capital, Nuku'alofa.
Guests packed the lavishly-decorated Centenary Church to see 27-year-old Prince Tupouto'a 'Ulukalala marry his second-cousin, Sinaitakala Fakafanua, 25.
The bride wore a long-sleeved lace dress with a floor-length veil, while the groom wore a three-piece black and grey suit.
Members of the Tongan royal family sat in elevated pews to the side of the altar as the bride and groom said their vows to the sounds of classical music and the church choir.
The Queen Mother, Queen Halaevalu Mataaho, and the Kings sister, Princess Pilolevu, did not attend the wedding as they reportedly disapprove of the union.
Outside the church, schoolchildren sung and clapped while waiting to catch a glimpse of the couple as they walked out of the church hand in hand.
Earlier, ONE News Pacific Correspondent Barbara Dreaver told TV ONE's Breakfast that ladies had been working throughout the night to finish the decorations at the church.
"And also I'm told there's been a storm of cooking going on."
Sound checks had been carried out and everything was on track for the wedding, Dreaver said.
It will be a "fairly straightforward" wedding service, she said, adding that protocols for a royal wedding have been followed in the lead up the ceremony. For example, a formal courtship ritual was held in which the bride's family took the groom's family to the house for entertainment and gift giving.
The formal guest list includes traditional families from Fiji and friends and family of the royal couple, Dreaver said.