Crystal Lake Aquathon

The Crystal Lake Aquathon, held annually at Three Oaks Recreation Area in Crystal Lake, Illinois, is the state's only aquathon event. The 8th edition in 2025 offers multiple timed race options including a Sprint Distance (500m swim, 5k run), Olympic Distance (1 mile swim, 10k run), a 2-mile swim, and a 1-mile swim. The swim takes place in a modified quarry around three islands, while the run covers trails, sand, and pavement.

There are also Kids' and Adaptive races with shorter distances and support options. Post-race festivities include food, awards for top finishers, and access to recreational activities at Three Oaks. Proceeds benefit Girls on the Run Northwest Illinois. Visit the organization's website for the most recent information.