Bear grew up in Donaghadee, County Down in Northern Ireland, before moving to Bembridge on the Isle of Wight, UK. His parents are Sir Michael Grylls and Lady Sarah Grylls. He learned to sail and climb from his father. He soon went on to become a Cub Scout. He joined the army after leaving school. In 1996, he suffered a freefall parachuting accident in Zambia while serving the army and crushed three vertebrae. He had to take much time off his adventures to recover from this accident.