Swallow is a very experienced wide left player, who helped local rivals Havant & Waterlooville to the Ryman (Bostik) Premier Division championship last season.
Originally from Cardiff, 27-year-old Swallow began his football career at his home-town club, before joining Bristol Rovers.
He made almost fifty Football League appearances for Rovers and also enjoyed loan spells at Taunton Town and Saturday's visitors, Bath City.
He then went on to play at York City, Newport County and Dartford in the Conference (National League) Premier as well as Bromley in the Conference South before joining Havant at this stage last year.
Calvin Davies (pictured) has also signed for the Rocks on a permanent basis.
The 19-year-old defender was released by SkyBet League One side Portsmouth at the end of last season – a season spent mostly on loan at Bognor, making thirty appearances.
Earlier in his career he had a loan spell with Havant and with the Rocks in January 2016.