Get ready to kick off an exhilarating race weekend at the Cambridge Half Marathon + 5K in picturesque Cambridge, MA, on Saturday, October 31, 2026. This popular 5K offers runners a fantastic opportunity to experience a fast and flat course along the Charles River. Starting and finishing at CambridgeSide, the 3.1-mile route is a quick out-and-back that provides stunning views of the Boston skyline. Expect typical race day conditions around this time of year, with comfortable highs near 58°F and lows around 43°F, and only a 15% chance of precipitation, creating ideal running weather.

The USATF-certified 5K course is renowned for its smooth, paved terrain, making it perfect for chasing a personal best. Runners consistently praise the inviting atmosphere and the scenic backdrop of the Charles River and prominent landmarks like MIT and the John W. Weeks Footbridge. Aid is readily available with one water stop along the course, and portable toilets are provided at Canal Park near the starting corrals. Beyond the race, participants contribute to a meaningful cause, as event proceeds benefit local charities such as the City of Cambridge Scholarship Fund and Cambridge Camping. Whether you're a seasoned runner or looking for a fun and scenic sprint, the Cambridge 5K promises a memorable race experience in the heart of Cambridge.