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.
Outside the church, school children 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 to today's 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.
Marriage draws controversy
Both the bride's parents are first cousins to her future father-in-law, the king, and this has drawn some controversy in Tonga, she said.
"It's fair to say there's a lot of people who feel this is the perfect match. However it has drawn a lot of controversy and also divisions within the royal family itself."
The king's sister and the queen mother disapprove of the marriage and will not be at the wedding, Dreaver said.
The wedding comes as the Tongan Government faces a vote of no confidence, 18 months after the island nation's first democratic elections.
A motion of no confidence has been filed by the opposition, backed by three Government ministers who recently resigned, sparking rumours that Prime Minister Lord Tu'ivakano's hold on power could soon be over.
The opposition has accused the Government of misappropriating funds and not doing its job. The vote of no confidence is expected to take place early next week.
Dreaver said it is a very serious situation for the country because the economy is very low "and this political turmoil is not helping at all".
She said the numbers on each side are very close and no one is sure whether the government will fall.
"It could go either way. So this uncertainty is just a breeding ground for economic hardship here."
Meanwhile, the frigate HMNZS Otago is currently in port in Tonga, on a visit unrelated to the royal wedding.
Dreaver said the Otago's crew, still recovering from the recent death of a crewman in a motor scooter accident in Rarotonga, is really flying the flag for New Zealand while in Tonga, working on projects such as painting schools.
"These are young men and women we should be very proud of," she said.