The Bayandor class comprises four Iranian patrol frigates originally built for the US Navy as the PF-103 class. Only two are currently in service. Two were sunk in 1980 by Iraqi Exocet ASM and aerial bombs.

A corvette is a small warship. It is traditionally the smallest class of vessel considered to be a proper warship. The warship class above the corvette is that of the frigate, while the class below was historically that of the sloop-of-war.