The Duke of York, Prince Andrew, and Bahrain's Crown Prince Salman bin Hamad Al Khalifah attended the opening ceremony of the UK Naval Support Facility in the tiny island's Salman Port on Thursday.
The base is located off the coast of Saudi Arabia and has room for up to around 500 Royal Navy personnel, including sailors, soldiers and airmen.
"The aim of the Royal Navy being out here anyway is to enhance and ensure the maritime security in the region, and whether or not that's law and order on the high seas, countering piracy, countering terrorism, making sure that the high seas are all safe for the free-flow of commerce, the free flow of trade to be able to take place," UK Maritime Component Commander Commodore Steve Dainton said during the opening ceremony on Thursday.
The base allows the UK Royal Navy to carry out longer-term deployments in the Persian Gulf and makes it easier to provide engineering and logistical support for British ships in the region.
British warships, specially the fleet of advanced Type 45 destroyers, have been struggling to stay afloat in the Persian Gulf's warmer waters. Constant power failures has on many occasions forced the £1bn warships of this specific class to sail back to the UK and undergo repairs.
The base is also designed to house mine sweepers and aircraft carriers, but much to the surprise of military experts, it won't be able to service the Royal Navy's own flagship, the HMS Queen Elizaebth aircraft career, due to shallow waters.
Bahrain also plays host to the US Navy's 5th Fleet, which is currently based at the HMS Jufair base.
London first established the HMS Jufair in 1935. The US military first leased space in the base in 1950 and then took control over the entire facility in 1971, following Bahrain's independence from the British Empire.
The two countries unveiled the plan to reestablish the British base in late 2014 and started construction nearly a year later.
The UK has helped Bahrain's ruling Al Khalifah monarchy to put down pro-democracy demonstrations across the country over the past years.
Meanwhile, Bahrain announced on Wednesday that it had discovered off-shore reservoirs of oil, estimated to contain at least 80 billion barrels of tight oil.
Tight oil is a form of light crude oil held in shale deep below the earth’s surface that is extracted with hydraulic fracturing, or fracking, using deep horizontal wells.
“Agreement has been reached with [American oilfield services company] Halliburton to commence drilling on two further appraisal wells in 2018, to further evaluate reservoir potential, optimize completions, and initiate long-term production,” Bahraini Oil Minister Sheikh Mohammed bin Khalifa Al Khalifa told a news conference in Manama.