HMS Defender shadows Russian naval task group along UK coastline (Picture: Royal Navy).
The Ministry of Defence has announced HMS Defender has been deployed to the Gulf of Oman.
The Type 45 destroyer left Portsmouth earlier this month bound for the Far East.
However, she has since been diverted to support the safe passage of British-flagged ships through the Strait of Hormuz.
Last month, Iran seized the British-flagged oil tanker Stena Impero, which remains held by the Islamic republic.
Defence Secretary Ben Wallace said: "Wherever the red ensign flies around the world, the UK stands by to protect freedom of navigation whenever is it tested."
Tensions have been increasing in the region following the breakdown of the Iran nuclear deal.
She will join HMS Montrose and HMS Kent in carrying out patrols in the region.