"In an operation lasting almost 10 hours, a team from the warship boarded a suspect in international waters off the coast of Oman and seized 663kg of heroin, 87kg of methamphetamine and 291kg of hashish and marijuana," the statement said.
"This is the largest Royal Navy drugs bust since last year, HMS Montrose seized 2.4 tons of illicit substances in the Arabian Sea," the MoD said.
A team from HMS Montrose approached a small vessel on two Rigid Hulled Inflatable Boat -- where after a search they were able to collect the illicit drugs -- before proceeding to analyze and destroy them.
According to MoD, HMS Montrose has been deployed to the region since early 2019.
The warship regularly works alongside international partners which make up the 34-nation coalition Combined Maritime Forces, which was led by the Royal New Zealand Navy at the time of the drugs bust. The leadership role has now passed to the Pakistan Navy.
The MoD said: "The Combined Maritime Forces (CMF) is a multinational maritime partnership, which exists to counter illicit non-state actors.
"This successful operation has prevented a large amount of illicit drugs from potentially reaching the UK and being sold on British streets. Organized criminals, often associated with the funding of terrorism, have also been denied a source of income," the statement said.
The Commanding Officer of HMS Montrose, Commander Claire Thompson said in a statement:
"Our enduring presence never wanes. Nine rotations into the forward deployed model, HMS Montrose remains as professional and enthusiastic as ever.
"Starboard Crew's relentless efforts have resulted in a substantial seizure of illegal narcotics and I am extremely proud of my team."
British Defense Secretary Ben Wallace also said: "The Royal Navy continue to step forward with our partners in the Combined Maritime Forces to stamp out the smuggling of illegal substances.
"As a result of this successful bust, our streets our safer and have choked off a huge source of finance to international organized crime groups."