HMS Decoy was an Ariel-class composite gunboat of the Royal Navy, built at Pembroke Dockyard and launched on 12 October 1871.

Designed by Sir Edward Reed, Chief Constructor of the Royal Navy, the Ariel-class gunboats were the first gunboats of composite construction.

All the ships of the class carried a three-masted barquentine rig.

In 1882 she formed part of the Naval and Military forces at the Bombardment of Alexandria.

[2] Argus, Isis, and Beacon blockaded Damietta.