Police are urging Canberrans to be vigilant around waterways after a man drowned on Christmas Day at a popular swimming hole in the territory.

As the temperature climbed to 30 degrees yesterday, many ACT families celebrated by cooling off at Casuarina Sands to the west of Canberra.

However, tragedy struck in the afternoon when a 27-year-old man was pulled unresponsive from the popular swimming spot on the Murrumbidgee River.

Police and paramedics were called to the river bank, but nothing could be done to save the man.

Police said they believed his death was not suspicious and will investigate the circumstances surrounding the drowning.

The death comes as another 27-year-old man drowned on Christmas Day at a busy beach south of Sydney.

ACT Policing have urged Canberrans to take care in waterways over the summer period.

A report will be prepared for the coroner.