Named after the River Medway in Kent, she was the second Batch 2 River-class vessel to be commissioned and is assigned long-term as Royal Navy guardship in the Caribbean.

On 6 November 2013, it was announced that the Royal Navy had signed an agreement in principle to build three new offshore patrol vessels based on the River-class design (more specifically, the larger Amazonas-class corvette derivative) at a fixed price of £348 million, including spares and support.

Rather than being launched in the traditional manner, Medway was rolled onto a semi-submersible barge and lowered into the water on 23 August 2017 and was officially named a few weeks later on 20 October 2017.

[17] In January 2020, Medway embarked on her first overseas deployment, assigned to Atlantic Patrol Task (North) on long-term guardship duties in the Caribbean.

[21] The Governor of the British Virgin Islands subsequently requested the assistance of Medway in securing the territory's borders in an effort to control the spread of the virus in late September.

[22] Mid-September also saw the involvement of Medway in a large counter-narcotics operation in conjunction with Argus, 47 Commando (Raiding Group) Royal Marines and the United States Coast Guard.

[27] In January 2023, Medway temporarily deployed to the Falkland Islands to take over the role of guardship there whilst her sister ship HMS Forth underwent maintenance.

[35] In June 2024, during post-refit sea trials off Gibraltar, the ship was reported to have run into mechanical problems and had to be towed back to the port for further work.