The da Vinci Decathlon is an academic competition designed to challenge and stimulate students' minds. Students compete in teams of eight across 10 disciplines. The decathlon competition was created by Knox Grammar School in 2005. The event's popularity has grown, and the da Vinci Decathlon is now run annually across all states and territories of Australia. After participating for several years, Canberra Grammar School became a charter school in 2008 for schools in Canberra and the region.

The 2025 regional Decathlon will take place on the following days:
• Years 5 and 6 | Wednesday, 30 April 2025
• Years 7 and 8 | Thursday, 1 May 2025
• Years 9 and 10 | Friday, 2 May 2025