Boston 2027 Registration Closes September 18

Published September 17, 2026 · Estimates, updated each registration cycle

Qualifier registration for the 131st Boston Marathon closes at 5:00 p.m. Eastern on Friday, September 18, 2026. That is a hard stop, not a soft one, and there is no late window, no waitlist and no second application period. If you hold a qualifying time inside the window and have not submitted it yet, this is the last full day to do it.

What 5:00 p.m. Eastern means where you are

Eastern Daylight Time is still in effect in September, so the deadline lands at 4:00 p.m. Central, 3:00 p.m. Mountain and 2:00 p.m. Pacific. Arizona does not observe daylight saving, which puts it at 2:00 p.m. as well. Alaska is 1:00 p.m. and Hawaii is 11:00 a.m., which is the one genuinely awkward case: a Hawaii runner who plans to file the application after work will be roughly six hours too late.

Treat the real deadline as several hours earlier than the published one. Registration is not first come, first served, so there is no advantage to submitting at the buzzer, and there is a clear disadvantage: the platform is busiest in the final hours of the final day, and any problem you hit at 4:45 p.m. Eastern is a problem you no longer have time to solve.

The things that actually go wrong late

Almost none of the failures in a registration week are about fitness. They are clerical. The recurring ones are a finish time typed from memory instead of the official results, a bib number that does not match the race record, the wrong race date, a name or date of birth that differs from the one on the result, and a payment card that declines the authorization. Each of those takes minutes to fix with the results page open in another tab, and each is unfixable once the window has closed. The full list is in mistakes that sink an application.

One point worth repeating on the last day: your age for qualifying purposes is your age on race day, April 19, 2027, not your age now. Runners with a birthday between today and the race sometimes qualify under a standard they did not realize they had reached. If you are close to an age group boundary, check that before you decide you have nothing to submit.

If you are still deciding

Our central estimate for the 2027 cutoff is about 5:15 under the standard, with a realistic range of roughly 3:30 to 7:00. That is an estimate, not a BAA figure. For context, the 2026 race settled at 4:34 and the 2025 race at 6:51. You can run your own time through the cutoff predictor to see where your buffer sits against that range and against every cutoff since 2014.

If your buffer is thin, the reasoning has not changed in the final hours: the fee is charged only on acceptance, a rejected application costs you nothing but the wait, and for 2027 an application that misses the cutoff still enters the random qualifier selection for about 1,000 places. Not applying is the only choice that guarantees a no. The longer version of that argument is in should you apply with a small buffer.

After the window closes

Nothing visible happens for a while. The BAA verifies submitted times, applies the new elevation index to qualifying times from courses with a net drop over 1,500 feet, then sorts the verified pool by buffer and fills the field. Applicants are notified of acceptance or non-acceptance by early October 2026, and the cutoff becomes public with those decisions rather than before them. See when the cutoff will be announced for what to expect in that gap.

If you miss the deadline, the next qualifying window opens the day after this one closes. Qualifying times for the 2028 race are accepted from races run on or after September 19, 2026, which means a fall marathon still counts for next cycle. The details are in the 2028 qualifying window, and the full calendar for this cycle is in the registration timeline.