Police were called to Gibraltar Falls, about 30kms south-west of Canberra, about 11.15am on Sunday, to reports a man had fallen off a cliff.
Describing the man as a swimmer, police said ACT Parks and Conservation rangers and passersby provided first aid until emergency services arrived but weren't able to save the man.
A host of first responders, including officers from various police divisions, paramedics, firefighters and a rescue helicopter, had rushed to the scene.
The waterfall is within the Gibraltar Special Purpose Reserve, near a walking track and boasts views of Gibraltar Creek and Paddys River valley, according to Parks ACT.
