Named after Omar Ali Saifuddien III, the 28th Sultan of Brunei who also initiated its construction, the mosque serves as a symbol of the Islamic faith in Brunei and dominates the skyline of Bandar Seri Begawan. The building was completed in 1958 and is an example of modern Islamic architecture.
Built in an artificial lagoon on the banks of the Brunei River at Kampong Ayer- the "village in the water", the mosque has marble minarets and golden domes, a courtyard and is surrounded by a large number of trees and floral gardens. A bridge reaches across the lagoon to Kampong Ayer in the middle of the river. Another marble bridge leads to a structure in the lagoon meant as a replica of a 16th Century Sultan Bolkiah Mahligai Barge.
The mosque's most recognizable feature - the main dome, is covered in pure gold. The mosque stands 52 m (171 ft) high and can be seen from virtually anywhere in Bandar Seri Begawan. The main minaret is the mosque's tallest feature. In a unique way it mixes Renaissance and Italian architectural style. The minaret has an elevator to the top, where a visitor can enjoy a panoramic view of the city.
The interior of the mosque is for prayer only, with features such as stained glass windows, arches, semi-domes and marble columns. Nearly all the material used for the building were imported from abroad: the marble from Italy, the granite from Shanghai, the crystal chandeliers from England and the carpets from Saudi Arabia.