Supermarine Sea Lion III

Sea Lion III
Henry Biard aboard the Sea Lion III in October 1923
Role Racing flying-boat
National origin UK
Manufacturer Supermarine Aviation Works
Designer R.J. Mitchell
First flight 1923
Retired 1923
Number built 1

The Supermarine Sea Lion III was a British racing flying boat built by the Supermarine Aviation Works. Designed by Reginald Mitchell, it was a modification of Supermarine's Supermarine Sea Lion II. It was powered by a 550 hp (410 kW) Napier Lion engine.

Sea Lion III was entered for the 1923 Schneider Trophy contest at Cowes. Supermarine's test pilot Henry Biard flew the aircraft and managed third place, reaching a speed of 151.16 mph (243.27 km/h). The performance of the Sea Lion III led to Supermarine designing seaplanes instead of flying boats as racers.