The Navy is using Special Boat Service snipers to intercept cocaine shipments heading to Europe from producers in Colombia and Bolivia.
A team of special forces soldiers was on board a Lynx helicopter on Sunday - also carrying Prince William - that spotted and stopped a smuggling vesselnorth-east of Barbados. The boat was en route to Europe from Latin America.
The Prince was among a team dispatched from his ship, HMS Iron Duke, which intercepted the 15m speedboat, known as a "go-fast".
American coastguards and British sailors who boarded the boat discovered more than 900kg of cocaine with a street value of £40 million ($104 million). It is believed the shipment was destined for cities in Europe.
The team aboard the Lynx became suspicious after spotting the power boat 320km out to sea, and arrested the five crew members on board. The boat, which was said to be in poor condition, sank soon after it had been searched.
Prince William had joined HMS Iron Duke, a 4900-tonne frigate, four days before the raid.
The ship, originally designed as a submarine hunter, is part of a counter-narcotics operation that has been stepped up following an increase in cocaine shipments from Latin America to Europe in the past two years. It is also tasked with providing humanitarian assistance from June to October, the core hurricane season.
Despite additional resources being devoted to tackling the illicit shipments, officials involved in drugs operations acknowledge that the risk of being caught is much less on this route than into the US, and traffickers who are apprehended once they are in Europe are rarely extradited.
The Prince was flown out to the Iron Duke by helicopter from Barbados. He is on a five-week training attachment and Commander Mark Newland, the ship's commanding officer, promised that the Prince "will contribute to all aspects of our operations, including counter-drugs and disaster relief planning".
