Where to start
There are generally three main branches of the Armed Services. In the UK each has a graduate recruitment website that is the natural starting point.
Royal Navy (including the Royal Marines)
Each branch offers three distinct types of role, namely those focussed on operations, combat and peacekeeping, those in specialist or technical activities and a wide range of support roles.
In applying you will be expected to satisfy basic medical, age and nationality recruitment criteria. The application, assessment and selection process can be lengthy compared to graduate recruiting in the civilian world.