Treat swimming as a skill
The dedicated Royal Marines CPC page describes a pool swimming assessment among its activities. Being able to run well does not automatically mean you can swim calmly, conserve effort or follow instructions in the water. Ask a qualified swimming teacher to assess technique in an appropriate facility before focusing on a military-themed workout.
Do not use breath-holding competitions
Static breath-holding, forced underwater laps and unsupervised confidence drills can create serious risk. None of these is required for ordinary civilian preparation. The Royal Navy's published requirements and your individual joining instructions—not online dares—are the basis for understanding assessment tasks. A qualified instructor can help identify skill gaps without risky experimentation.
Pool and open water are different environments
A swimming pool offers consistent conditions and supervision. Rivers, reservoirs and the sea add cold, current, changing depth and weather. The RNLI recommends checking conditions, swimming with others and respecting personal limits. A general Royal Marines aspirant does not need to convert every swim into an open-water event.
Practise clear, ordinary competence
Within a supervised setting, useful questions include whether you can follow instructions calmly, maintain efficient breathing and recognise when to stop. The appropriate technical exercises depend on your ability and the judgement of your instructor. No written guide can assess someone’s water safety remotely.
When concerns are more than confidence
If you have a medical concern, a history of a water incident or persistent symptoms during exercise, seek qualified advice rather than attempting self-testing. The objective is sustainable skill, not an unofficial pass prediction.
An exercise to make this useful
Contact a local qualified pool instructor with two questions: what should I learn first, and how will we keep practice supervised? Keep any official military assessment questions for your recruiter.
Use the free planning tool ↗Verify before you act
Sources and official guidance
These references support the published pathway or general safety guidance. An independent exercise is our own educational example; it does not reproduce military assessments. Check any changed requirements directly with the responsible authority.