21 SAS vs 23 SAS vs 22 SAS
By Deepak Shukla · Historical account and source-led commentary · Updated
22 SAS is the regular, full-time SAS regiment. 21 SAS and 23 SAS are reserve regiments whose members keep civilian careers and train alongside them. All three form part of United Kingdom Special Forces; the practical difference for anyone applying is full-time service versus reserve service.
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22 SAS
The regular regiment, based in Herefordshire. Soldiers serving in 22 SAS do it as their full-time job, and the usual route in is from an existing career in the regular Army rather than from civilian life.
21 SAS and 23 SAS
21 SAS and 23 SAS are Reserve regiments. The British Army lists broad recruiting regions for each and describes a reserve service pathway with training alongside civilian life. Geography is one important practical factor, but it does not by itself determine eligibility or tell you which current opportunity is available. Use the official recruiting route for that advice.
What is the same
The Army describes demanding training and service requirements for the Reserves. My own experience was limited to application and preparatory Army courses; I did not attempt either Regiment's SAS selection and cannot compare their assessments from direct experience. I can speak to the real challenge of balancing a civilian life with Army training.
Which should you apply to?
If you are exploring full-time military service, begin with the Army's current regular careers guidance. For the Reserves, check the official SAS Reserve role listing and ask recruiters which unit and pathway suit your circumstances. Do not assume that reserve service is a shortcut into a regular Special Forces role.
Does 'same selection' mean identical recruitment?
Not necessarily. The Army describes common UKSF selection elements, while its Reserve and Regular recruiting arrangements and initial eligibility can differ. For 21 versus 23, the published recruiting regions differ. Don't infer that an older candidate story establishes the current exact duration or test sequence for every pathway.
A note on accuracy
Entry criteria, standards and selection dates are set by the Army and change over time. Take anything current from the Army's own UK Special Forces Reserve pages; take everything below as one applicant's experience.
Sources and current requirements
My experience dates from 2014–2016. Eligibility, fitness standards and the selection process change, so for anything current use the Army's own pages:
- British Army Jobs — SAS Reserve role, entry requirements, selection and locations
- British Army — UK Special Forces Reserve overview and recruiting contact
- British Army — 21 and 23 Special Air Service Reserve
- Soldier magazine (October 2025) — SAS Reserve recruiting feature
Rechecked 7 November 2026. The Army Jobs listing and the October 2025 Soldier article use different age wording — ask the recruiting unit rather than picking the convenient figure.
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Get my 21 SAS application and preparation guide
What I actually did during Army preparation, what I learned, and a general twelve-week fitness framework informed by endurance sport. It is not a military selection programme; current standards come from the Army.