Around 40 children have been put through their paces this week by Royal Marines from 42 Commando.
All of the youngsters are members of Her Majesty's School Heroes, a support group for children of service men and women.
The workshop, at Bickleigh Barracks in Plymouth, gave them the chance to do commando-style challenges.
A Cornish MP has criticised the standard of body armour given to Plymouth-based 42 Commando. Sheryll Murray has been following the Royal Marines in training in California, where they are using old-style armour.