In 2010, planning for The Swarm began behind closed doors. The ride was codenamed Project LC12 in the early process of its planning and construction. On 31 January 2011, Thorpe Park submitted a planning application for their 2012 ride to the Runnymede Borough Council. The website gave further information about the new ride's theme, that of an apocalyptic battle.
At the time of the ride's announcement construction was already underway. The track for The Swarm was complete by 18 November 2011. Clearance testing started almost immediately; the first operational test run was completed on 17 January 2012.
On 15 March 2012, The Swarm officially opened to the public. In January 2013, Thorpe Park announced that the last two rows on The Swarm would be rotated to face backwards for 2013, a first for a Wing Coaster. The park's tag line for this experience is 'THE SWARM- Brave It Backwards'. The park additionally announced that they were adding a damaged, mangled billboard, which the train travels through. In 2016 the seats were returned to all facing forwards.
