The mosque is lit up at night.
The 10-day wedding of Prince Mateen and his girlfriend Anisha RosnahIsa-Kalebic began on Sunday.
They were showered with blessings from their families during the Berbedak Mandi, or powdering ceremony before the duo arrived at the mosque to exchange vows on Thursday.
Prince Mateen, 32, is Sultan Hassanal Bolkiah's 10th child and is sixth in line to the throne. A helicopter pilot and a major in the Royal Brunei Air Force, he has also played polo for his country in the 2017 and 2019 SEA Games.
Hong Kong's Tatler Magazine listed him among Asia's top 50 most eligible bachelors in 2016.
Anisha Rosnah binti Adam is the granddaughter of the Sultan's special advisor.
She graduated from a prominent university in England, runs a fashion label, and co-owns a tourism business with a friend.
Photo by Wiki/Sam Garza