Boston Marathon 2024 Registration Form. The 2025 boston marathon qualifying window began on september 1, 2023, and closed at 5:00 p.m. The field size for the 128th edition of the race,.

For the 2024 boston marathon, qualifying times must be run on or after thursday, september 1, 2022. The 2025 boston marathon qualifying window began on september 1, 2023, and closed at 5:00 p.m.