Breaking (also known as breakdancing) is the newest Olympic sport, having debuted at the 2024 Paris Olympics.
2. Surfing — 2021
I had no idea surfing was so new, but it actually wasn't even in the Olympics until the Tokyo Olympics in 2021 (actually dubbed the 2020 Games because the pandemic messed some of those dates up).
3. Skateboarding — 2021
Also new in the 2021 Tokyo Olympics was skateboarding, which the Olympics themselves described as a "roaring success" a year after its debut.