WARSHIPS based in the city have secured the safety of seven million tonnes of British shipping.
Crews from Portsmouth-based HMS Kent, Duncan and Defender guarded the ships through the Strait of Hormuz - which is double the size of Wales - in and out of the Gulf.
It comes as tensions flare over boats being seized.
Type 23 frigate HMS Kent spent three weeks guarding 800,000 tonnes worth of shipping on British flagged and registered merchant vessels.
Commander Andrew Brown, the ship's commanding officer, said: 'We are a close-knit team and I am extremely proud of what my sailors have achieved over the last few months.
'This has tested our skills and resilience – and every single person onboard has delivered for me professional excellence throughout, providing invaluable reassurance to merchant shipping in a key waterway.'
She deploys her Wildcat helicopters to check for danger.
Leading Aircraft Controller Lewis Jackson said: ‘Controlling our helicopter in such a busy area of the world can at times be extremely stressful.’
‘The constant training we receive enables us to do our job in a calm and safe manner and at an extremely professional level.’
READ MORE: Crews called into action in the Gulf
Hundreds of people welcomed HMS Duncan home on Saturday after she made 29 trips through the Strait.
The ship safeguarded nearly than 1.3m tonnes of merchant shipping.
Commander Tom Trent said: 'Protecting shipping is what the Royal Navy has done for hundreds of years.
'The whole operation is a reminder of how critical the Royal Navy is.'