Boston 2027 Registration Week: A Checklist

Published September 7, 2026 · Estimates, updated each registration cycle

Qualifier registration for the 2027 Boston Marathon opens on Monday, September 14, 2026 and closes at 5:00 p.m. ET on Friday, September 18. It is not first come, first served, so the week rewards accuracy rather than speed. Everything below is worth doing in the seven days before the window opens, because none of it is quick to fix once the clock is running.

Do these before Monday

• Log in to Athletes' Village now. Applications go through the BAA's own platform, and the worst time to discover a forgotten password or a dead recovery email address is the morning the window opens. Log in this week, reset anything that does not work, and make sure the account is under an email address you actually read.
• Check that your personal details match your qualifying race. Name, date of birth and gender on your BAA profile need to match the result the BAA will verify. A middle name in one place and not the other is a common reason a legitimate qualifier gets held up, along with the other errors in the application mistakes guide.
• Confirm your race is inside the window and certified. The qualifying time must come from a certified marathon run inside the published window for 2027. If you are not certain of the certification status, look it up now rather than guessing.
• Write down the time to the second. Official net time, plus race name, race date and location. Do not work from memory or from a watch file. Pull the official result page and copy it exactly.
• Decide which time you are submitting. If you have more than one qualifier in the window, the fastest clock time is not automatically the strongest application now that the time index applies to steep courses. The comparison guide walks through how to choose.
• Know the net drop of your course. For the first time, 2027 registration adjusts times run on courses with more than 1,500 feet of net elevation drop. If your race is one of them, work out your adjusted time before you apply so the number on screen is not a surprise.
• Check your card. The application takes a payment authorization, so use a card that is valid well past early October and is not about to be reissued.

During the week itself

Applying on Monday gives you no advantage over applying on Thursday. The BAA collects every application first and only then applies the cutoff to the whole pool, which is why the published timeline matters more than the hour you hit submit. What is worth avoiding is the last afternoon: if something on your application needs a correction, a support reply, or a document you have to dig out, you want days of slack rather than hours. Aim for Tuesday or Wednesday and keep the confirmation email.

What you cannot change now

Your buffer is fixed. Training and racing decisions are behind you, and the only open question is where the cutoff lands. The working estimate for 2027 is roughly 5:15 under the standard, with real uncertainty on either side of that. If your buffer is close to that line, apply anyway: there is no penalty for an unsuccessful application, and qualifiers who miss the cutoff now fall into the new random selection for about 1,000 places. You can check what your own buffer is worth against thirteen years of real cutoffs with the cutoff predictor before you fill anything in.