RFA Lyme Bay is a Bay-class auxiliary dock landing ship of the British Royal Fleet Auxiliary (RFA). Ordered from Swan Hunter in 2000, the ship was launched in 2005. However, cost overruns and delays saw the shipbuilder removed from the project, and the incomplete ship was towed to Govan for finishing by BAE Systems Naval Ships. Lyme Bay entered service in late 2007; the last ship of the class to join the RFA.

The Bay class is a ship class of four dock landing ships built for the British Royal Fleet Auxiliary (RFA) during the 2000s. They are based on the Dutch-Spanish Royal Schelde Enforcer design, and replaced the Round Table-class logistics ships. Two ships each were ordered from Swan Hunter and BAE Systems Naval Ships. Construction work started in 2002, but saw major delays and cost overruns, particularly at Swan Hunter's shipyard. In mid-2006, Swan Hunter was stripped of work, and the incomplete second ship was towed to BAE's shipyard for completion. All four ships, Largs Bay, Lyme Bay, Mounts Bay, and Cardigan Bay had entered service by 2007.