The Ahmad Yani class of six general-purpose frigates were acquired by the Indonesian Navy in the 1980s.

They were originally built in the Netherlands for the Royal Netherlands Navy as the Van Speijk class which were licence-built versions of the British Leander class.

At 6:07, the Lusitania Expresso had traveled two to three nautical miles (3.7 to 5.6 km; 2.3 to 3.5 mi) into Indonesian territory and Captain Luis Dos Santos (Lusitania Expresso's captain) was ordered to leave immediately.

[2] All six frigates have had their steam turbine power plants replaced with marine diesel engines.

[5] The frigates of the Ahmad Yani class are due to be replaced by the Martadinata-class frigates (SIGMA PKR 10514); the first of which, Raden Eddy Martadinata (331), was commissioned on 7 April 2017.