The Southampton's origins can be traced to an earlier experimental aircraft designed by R.J. Mitchell at Supermarine, the Swan, which made its maiden flight on 25 March 1924.

During this time, the Royal Air Force (RAF) was close to giving up on the procurement of effective large flying boats, having been disappointed by types such as the Felixstowe F.5.

[2] Having been impressed by the Swan's performance during trials at RAF Felixstowe, the British Air Ministry generated Specification R.18/24 and ordered a batch of six production Southamptons from Supermarine.

[5] While this flight was largely successful, one of the wingtip floats sustained minor damage, leading to their angle of incidence being quickly adjusted to prevent reoccurrence prior to their complete redesign later on.

These were passed with relative ease, including its ability to maintain altitude on only a single engine, leading to the aircraft's formal delivery to the RAF occurring during mid-1925.

Supermarine lacked the factory capacity to keep up with demand, thus an additional facility were acquired on the other side of Southampton Water, after which production of the type was centred in this location.

[5] Throughout the type's production run, the Southampton's design continued to be refined; changes included improved engines models and the substitution of the wooden hull and its wings with metal (duralumin) counterparts.

[10] Andrews and Morgan observed that the Southampton quickly proved itself to have primacy amongst European flying boats of the era, a fact that was promptly demonstrated by its overseas activities.

[12] These aircraft featured various technical changes, including enlarged fuel tanks composed of tinned steel, increased oil tankage, greater radiator surface area, and the removal of all armaments.

[16] One RAF aircraft was loaned to Imperial Airways, with British Civil Registration G-AASH, for three months from December 1929 to replace a crashed Short Calcutta on the airmail run between Genoa and Alexandria.

[17][18] Different powerplants were fitted in variants: The restored wooden fuselage of Supermarine Southampton 1 N9899 is on display at the Royal Air Force Museum in Hendon.