Tern Island was the idea of one of the park's former wardens. It was to improve upon the rafts that had provided nesting areas for terns by providing a more natural environment. The funding came from Natural England's Aggregates Levy Sustainability Fund Grant Scheme, a scheme to support projects that reduce the impact of aggregate extraction on local communities. Work began in November 2009 and was completed in February 2010.

The island was created from one that was already in place but moved further out into the lake to reduce accessibility to predators, also the vegetation was removed and a membrane put in place to impedere growth. Shingle was then added on top and shallow shelves created to provide habitat for waders and help chicks that accidentally wander off the island.