The School boasts over 40 clubs and societies in which children can become involved. Many are managed by the pupils themselves, from Bridge and the Christian Union to running the school telephone system. The large and voluntary CCF at Alleyn's is active and is divided into Navy, Army and RAF sections, all of which provide adventure training, camps and trips overseas. Activities within the CCF are varied, covering shooting, sailing, gliding, orienteering, abseiling, parachuting, canoeing and first aid. Pupils may join at the age of 14 or 15 and then stay in the CCF for a minimum of two years.
Cadets learn skills of self discipline, resourcefulness and leadership.
During the holidays CCF members have the opportunity to be put to the test further afield. All activities are free or heavily subsidised by the Ministry of Defence. Pupils opting for the Duke of Edinburgh Award Scheme are assessed on activities which must include Expeditions, Community Service and Physical Recreation. During Bronze expeditions in Surrey and Gold expeditions in Wales they learn to fend for themselves, to appreciate each other's strengths and weaknesses and to work as a team. The School has produced nearly 100 holders of the Gold Award.