In 1878 Armitage enlisted as a cadet aboard the Royal Navy's training ship, HMS Worcester, which was moored at the time in the River Thames near Greenhithe. At the conclusion of basic training he attempted to resign from the Navy and seek a position with the Peninsular and Oriental Steam Navigation Company (P&O), but was prevented from doing so by his father. Instead, Armitage was signed on as an apprentice aboard the former Indian Navy frigate Punjaub, now owned by the East India Company. He sailed with Punjaub to Calcutta, where he transferred to another Company vessel, the Lucknow, as Third Mate.
After seven years as a Company sailor, Armitage again sought parental consent to join P&O. Approval was received and in 1886 Armitage was appointed Fifth Officer aboard the P&O passenger ship Bokhara
Armitage was then Robert Falcon Scott's navigator and second-in-command on the Discovery Expedition to Antarctica. The other members were Ernest Henry Shackleton, George Mulock, Edward Adrian Wilson, Charles Royds, Frank Wild, Koettlitz, Skelton, Heald, Barne, Plumley, Quartley, Weller, Hare, Allen, Evans, Ferrar, Hodgson, Louis Bernacchi, Vince. On this expedition, he became the first person to walk on the polar plateau.
- Walton 1985, p. 511
- Walton 1985, pp. 512-513
Walton, D.W.H. (1985). "Profile: Albert Borlase Armitage" (PDF). Polar Record. Cambridge, United Kingdom: Scott Polar Research Institute. 22 (140). doi:10.1017/S0032247400005969. Retrieved 11 October 2014. (subscription required (. ))