The Unit
SBS(R) is the reserve arm of the United Kingdom's Special Boat Service — the Royal Navy's tier-one maritime special-forces regiment. Where the SAS reserves (21 and 23) handle the land side of UK Special Forces (Reserve), SBS(R) handles the water: maritime counter-terrorism, beach reconnaissance, ship-boarding and amphibious operations, mirrored at reserve scale.
It completes the four-part picture of the UKSF reserve — 21 SAS, 23 SAS, SBS(R) and 63 (UKSF) Signals — the part-time component that backs the regular SAS and SBS on exercises and operations.
The Gate
Here is the key difference from the SAS reserves: SBS(R) takes only applicants with prior military service. There is no off-the-street civilian route. Members of the Royal Marines Reserve with two or more years' service can apply, as can other regular and reserve personnel — men and women alike.
Applicants must be no older than 42½ at the start of the Aptitude phase, and ready to commit to intense, extended training and to deploy.
Selection
SBS(R) shares the UK Special Forces selection architecture, with a maritime edge.
The fitness gates
Demanding entry standards up front: a 13 km ruck-run carrying 25 kg inside 1 hour 50, then a 500 m non-stop swim and a water-retrieval exercise — the water work that defines the Service.
UKSF assessment
The arduous 6-day Briefing Course (BC) — common to UK Special Forces — assesses suitability for continued progression; those who pass choose a selection pathway, regular or reserve.
Aptitude & beyond
The reserve Aptitude phase and continuation run the same hills and the same standards as the regulars, condensed into weekends and blocks, before badging into the Service.
The Standards
The published SBS(R) gates make the maritime emphasis explicit:
Train To The Standard
SBS(R) rewards the strong swimmer who can also carry weight fast. The Gate's Selection tier maps the run, ruck, swim and strength base it's built on.