The 2027 Boston Marathon, set for April 19, 2027, will require participants to achieve specific qualifying times based on their age and gender. The qualifying window opened on September 13, 2025, and will remain open until September 2026. Runners must be at least 18 years old on race day to qualify. Notably, starting in 2027, courses with a net downhill of 6,000 feet or more will be ineligible for qualifying times. The Boston Athletic Association (B.A.A.) will apply time adjustments for downhill courses, adding five minutes for net downhills of 1,500 to 2,999 feet and 10 minutes for 3,000 to 5,999 feet. Due to limited spots, not all qualifiers will be accepted; entry will prioritize the fastest runners in each age and gender group. For those without qualifying times, entry through the Boston Marathon Official Charity Program is available, allowing runners to raise funds for nonprofit organizations. A list of participating charities can be found on the B.A.A.'s website.