HMS Leander (F109) was the nameship of the Leander-class frigate of the Royal Navy (RN). She was originally intended to be part of the Rothesay class and would have been known as Weymouth. Leander was, like the rest of the class, named after a figure of the classical Greek mythology. She was built by the Harland & Wolff shipyard in Belfast, Northern Ireland and was launched on 28 June 1961. She was commissioned on 27 March 1963.

The Ikara missile was an Australian ship-launched anti-submarine missile, named after an Australian Aboriginal word for "throwing stick". It launched an acoustic torpedo to a range of 10 nautical miles (19 km), allowing fast-reaction attacks against submarines at ranges that would otherwise require the launching ship to close for attack, placing itself at risk. By flying to a distant target, the engagement time was dramatically shorter than provided by short-range weapons, giving the target less time to respond.