Devonport-based frigate HMS Argyll returned to base on Wednesday after six months at sea.
HMS Argyll has a 180-strong crew
The Type 23 frigate travelled 27,500 miles (44,255km) as part of Operation Telic in the Northern Gulf working with forces from the USA.
The 180-strong crew helped protect oil installations in Iraq, which provide the country with 80% of its export oil and are vulnerable to attacks.
Argyll also carried out humanitarian missions during her time away.
'Training and preparation'
HMS Argyll worked hard to ensure safety and security for the oil tankers and their crews in the gulf, as well as merchantmen ferrying goods around the region and the hundreds of fisherman who ply the rich waters for their daily catch, the Royal Navy said.
This involved patrolling the area and stopping, boarding and searching about 65 merchant vessels to verify their cargo, to deter oil and arms smuggling.
The ship's humanitarian missions included sending out the ship's doctor to save a seriously burned merchant sailor, and a sick fishing boat crew.
Commanding Officer Commander Will Warrender said: "HMS Argyll had a tremendously successful deployment witnessing improvements for Iraq that were directly related to our actions in the Northern Arabian Gulf.
"Our training and preparation for this deployment proved to be successful and we should be proud in the knowledge that what we have done has helped the Iraqi people.
"Now, though, is a time for our families and loved ones who have carried on without us for the last six months.
"HMS Argyll is not just about the 180 sailors on board, but the hundreds of loved ones at home who support us and allow us to do our job."