The Johore Battery was a former British coastal artillery battery located in Changi on the easternmost side of mainland Singapore. It consisted of three large BL 15-inch Mk. I naval guns installed on land by the British government in the late 1930s to defend the approaching path to the east of the island to their large naval base located at Sembawang in the north (accessed via the Johor Straits) from an attacking enemy naval force.