The unit at RNAS Felixstowe was created soon after the outbreak of World War I, under the command of Lieutenant-Commander John Cyril Porte.
As the name implies, the unit designed seaplanes and flying boats. These were generally known by the Felixstowe name although, apart from the prototypes, these flying boats were built by aircraft manufacturers such as Short Brothers, Dick, Kerr & Co. and Phoenix Dynamo Co Ltd (the latter two forming part of English Electric in 1918-1919).
Upon Porte’s recommendation, the station was initially equipped with Curtiss flying boats. He improved their hull designs, before developing the Felixstowe flying boats from those experiments. Many Felixstowe boats were built under licence in the USA. The craft were flown on long-range patrols to spot the German High Seas Fleet and Zeppelins, with many based at RNAS Felixstowe.
In 1916 they ran trials in conjunction with the Submarine Service at Parkeston Quay to test the carriage and launching of seaplanes carried on the deck of submarine E22.
On formation of the Royal Air Force in 1918, the unit was renamed the Seaplane Experimental Station, Felixstowe and was disbanded in June 1919.
The base and its facilities were later used by the Marine Aircraft Experimental Establishment from 1924 until the Second World War. It was also used as a base by the Schneider Trophy team, the High Speed Flight.