The class name comes from the River Tamar in south west England which flows into the English Channel, where the hulls from SAR Composites were fitted-out by Babcock International Group.

The organisation desired to increase the speed and range of their operations so introduced faster Severn and Trent boats starting in 1994 at locations where they could be moored afloat.

It was sold in December 2008 to Kent Police, becoming Princess Alexandra III, the force's permanent maritime vessel operating out of Sheerness.

The 27th and last Tamar-class lifeboat, allocated to The Mumbles, was launched 12 March 2013 in Devonport Dockyard and after sea trials was handed over to the RNLI on 21 May 2013.

[6][2] Ten lifeboat stations keep Tamars moored afloat, 13 launch them down slipways, and the remaining four form a Relief Fleet to cover when boats are unavailable for service.

[citation needed] All Tamar Class lifeboats have sea water sourced open loop heat pump systems on board to keep the crew comfortable in high or low temperature conditions.