HMS Euryalus was a fourth-rate wooden-hulled screw frigate of the Royal Navy, with a 400-horsepower (300 kW) steam engine that could make over 12 knots (22 km/h; 14 mph).

Euryalus arrived at Yokohama on 15 September 1862, the day following the Namamugi Incident, a samurai assault on British nationals on the outskirts of the treaty port that led to a major breakdown in Anglo-Japanese relations.

[8] In an effort to enforce reparations from the Satsuma Domain, Euryalus served as Admiral Sir Augustus Kuper's flagship during the bombardment of Kagoshima on 16 August 1863.

During the bombardment of Kagoshima the Captain of Euryalus, John James Steven Josling, was killed, as was his second-in-command, Commander Edward Wilmot, both decapitated by the same cannonball.

The Euryalus's Captain of the Afterguard, Thomas Pride, was awarded a Victoria Cross for his actions during one of the stormings at Shimonoseki.