Fort Pembroke was another of the fortifications recommended by Colonel Jervois in 1866. The building of the Fort was approved in April 1873 with work commencing two years later. Fort Pembroke was primarily built as a adjunct to the North West Defences (Victoria Line). The Fort protected the eastern flank of the Victoria Lines along with Fort Madalena. In 1879 the following armament was approved for the Fort:
- Three 11-inch 25-ton RML guns in barbette mountings
- One 64-pdr on a disappearing gun carriage
- One field gun in a prepared position on the northern corner of the fort
- 32-pdr SB guns for the counterscarp galleries
The entrance to the fort was protected by an outworks (fleche) which also had a platform to mount field guns. This fleche at Fort Pembroke is similar to the one in Fort San Leonardo but has now been lost.
With the introduction of breech loading guns that came at the end of the 19th Century, a new 9.2-inch battery was built just outside the Fort, Pembroke Battery.