During the First World War there was still prosperity from visitors (unable to go abroad) and the influx of armed forces, as had occurred in the Napoleonic period. There was a cavalry depot, this time in Victoria Drive, and a large convalescent camp, west of Summerdown Road. The 'Blue Boys' uniform became a familiar sight around the town. Later the infirmary of the old Workhouse (built as a barracks in 1780) became a Military Hospital, as did several large houses.

A Royal Naval Air Service flying school was established near St. Anthony s Hill, on the airfield belonging to the Eastbourne Aviation Company. This Company made over 200 Avro fighter aircraft during the 1914-18 war. There was also an airship station near Polegate, and production of munitions by local firms at Eastbourne s omnibus depot.

During the 20 years between the wars the town continued to develop as a holiday resort. Parks and gardens were laid out, the central bandstand was built and 4,000 acres of the Downs were purchased by the Council to prevent development. Both private and Council housing estates were built in Old Town, Seaside and Hampden Park. Other public works, such as the Willingdon By-pass road, were carried out by unemployed from other areas.

A troop of soldiers marching from Summerdown Convalescant Camp to the Station.