The Fremantle-class patrol boats were coastal patrol vessels operated by the Royal Australian Navy (RAN) from 1979 to 2007. Designed by British shipbuilder Brooke Marine and constructed in Australia by NQEA, the Fremantle class were larger, more powerful, and more capable than the preceding Attack class, and the two primary patrol boat bases required infrastructure upgrades to support them. Although up to 30 vessels were planned, fifteen were ordered and constructed, with an unexercised option for five more.

A patrol boat is a relatively small naval vessel generally designed for coastal defence, border security, or law enforcement. There are many designs for patrol boats, and they generally range in size. They may be operated by a nation's navy, coast guard, police, or customs, and may be intended for marine, estuarine, or river environments.