Castra Falls is a waterfall on the Castra Rivulet in northwest Tasmania, near Nietta, and forms one of the highlights of the Castra Circuit.

The falls drop in a single plunge of approximately 10 metres into a pool enclosed by steep, small cliffs, with a series of cascades visible behind the main drop.

Reaching the base requires descending an extremely steep, slippery track from the circuit path above. Rope rails have been installed to assist hikers both down and back up. The full return hike to Castra Falls covers around 6.

5 kilometres and is rated Grade 4, suited to experienced bushwalkers. The circuit also passes several other waterfalls, including Silver Falls, Step Falls, and Castra Cascades, all set within impressive native forest.