Although part of the Borough of Hastings, and an ancient parish in its own right, the area that became known as St Leonards-on-Sea was only laid out in the 19th Century in its present form by James Burton as a place of elegant houses designed for the well-off who wished to take the sea air. There are many roads of fine housing, and the design also included parks and gardens. One such is Gensing Gardens, in London Road; another is West St Leonards Gardens, with its handsome portico entrance; a third is Warrior Square Gardens on the sea front.

The sea-front continues that of Hastings to a total of more than three miles. Until the Second World War there existed a St Leonards Pier, situated opposite the Royal Victoria Hotel. At the outbreak of the war it, like most other south coast piers, was deliberately cut in half to prevent enemy invaders using it; after the war it was in such a state of dereliction that it was completely demolished.

There were three train stations: St Leonards (Warrior Square) served by both routes from Hastings to London. West St Leonards was on the route to Charing Cross; and St Leonards (West Marina) served the coast route. The junction for the two routes was called Bo-Peep Junction, named after a nearby public house. The last-named station is now closed.

The principal shopping streets are London Road and Kings Road.