Recognised as a national landmark, Sultan Omar Ali Saifuddien Mosque is located in Bandar Seri Begawan, the Capital City of Brunei, situated on the island of Borneo, surrounded by Malaysia and the South China Sea. Named after Omar Ali Saifuddien III, the 28th Sultan of Brunei, the mosque serves as the symbol of the Islam in the country. Surrounded by an artificial lagoon that reflects its crowning glory, the gleaming golden dome, the mosque is an exclamation point above the Brunei River and the so-called village on the water, Kampong Ayer.

There is a decorative stone barge in the middle of the lagoon, which is a replica of a 16th-century mahligai or royal barge, resembling a ship of Sultan Bolkiah, who reigned the country in the 16th century, at the peak of the Bruneian Empire. Despite the flashy exterior of the mosque and the ceremonial boat in the artificial lagoon, which initially seem to be created to make it a place of tourist attraction, the splendid mosque was designed solely for prayer to Allah and nobody is allowed to enter inside, except for prayer.

Before it was renamed Bandar Seri Begawan in 1971 by Sultan Omar Ali Saifuddien, the capital city, known as Pekan Brunei,had only a small mosque built of timber and named Masjid Marbut Pak Tungal. The roof of the mosque was made of palm fronds and it could accommodate 500 worshippers at a time. The country, known as Brunei Darussalam during those days, was among one of the poorer nations in the world at the end of the First World War. However, with the discovery of oil and gas in Padang Berawa in July 1928, the situation changed dramatically and the country became one of the prized colonies of the British in the Southeast.

Much later, after ascending the throne in 1967, Sultan Omar Ali Saifuddien, a well-educated and devout Muslim, known as the architect of modern Brunei, started to construct the Sultan Omar Ali Saifuddien Mosque.

Designed by the Italian architect and sculptor Rudolfo Nolli, the construction work of the mosque began on 4 February 1954 and it took almost five years to complete it at a cost of around US$ 5 million. While its main dome is of pure gold, Italian marble was imported for its pillars and floor, granite from Shanghai, crystal chandeliers from England and ornate carpets from Saudi Arabia. The majestic building, influenced by Mughal architecture and measuring about 225 by 86 feet (69 by 26 m), with the capacity to accommodate 3,000 worshippers at a time, was inaugurated on 26 September 1958, in concurrence with the 42nd birthday celebration of Sultan Omar Ali Saifuddien III.

Covering an area of 5-acre (2.0 ha), Sultan Omar Ali Saifuddien Mosque, with its golden dome and the main minaret rising 171 feet (52 m) high, can be seen from anywhere in the City of Bandar Seri Begawan. The minaret is equipped with an elevator that takes the visitors to the top, from where the visitors can enjoy a panoramic view of the city. The ceremonial stone boat sitting in the middle of the artificial lagoon was completed in 1967 to commemorate the 1,400th anniversary of Nuzul Al-Quran, when the words of the Quran were first revealed to the Prophet Muhammad. A marble bridge leads across the lagoon to the decorative stone barge, where the Quran reading competitions are held.

Despite the flashy exterior of the mosque and the ceremonial boat in its artificial lagoon, the interior is almost as lavish as the exterior. While the floor and walls are made from the finest Italian marble, the floor is covered with handmade Axminster carpets from Belgium and Saudi Arabia. The beautiful chandeliers that illuminate the interior were crafted in England and a 3.5-million-piece glass mosaic overlaying real gold leaf covers the main dome.

The huge main chandelier, 15 feet (4.6 m) in diameter and weighing more than three tonnes, holds 62 fluorescent tubes. Apart from that, the interior is additionally lighted by an addition of more than 480 tubes.

Sultan Omar Ali Saifuddien Mosque in Brunei, evidencing the wealth of Brunei, is restricted only for the Muslims. However, reckoned as one of the most beautiful mosques in Southeast Asia, it is undoubtedly a major landmark and tourist attraction of Brunei.