Buzón Tributario: fines from January 2027 and how to enable it

In short: the Buzón Tributario (SAT’s tax mailbox) is the official channel SAT uses to notify you. Enabling it was already mandatory, but the fine was on hold. Starting January 1, 2027, SAT can fine anyone who does not have it enabled $3,850 to $11,540.

What is the Buzón Tributario?

It is a system inside SAT’s portal where the authority sends you notifications, information requests, invitation letters and notices, and where you can also file submissions. Whatever arrives in the mailbox counts as notified even if you never open it.

That is why not having it enabled is doubly risky: on top of the fine, you can be notified of something important and have deadlines run without knowing it.

Who must have it?

All individuals and legal entities registered in the RFC that must file returns. The 2027 change hits RESICO taxpayers hardest, since the RMF 2026 had deferred their penalty until January 1, 2027.

How to enable it step by step

1. Go to SAT’s portal, Buzón Tributario section, with your RFC and password or with your e.firma.
2. Register at least one email address and a mobile number as contact methods (you can register up to five email addresses).
3. SAT sends a code to each contact method. Confirm them within 72 hours; otherwise the request is cancelled and you have to start over.
4. Check that the status says your contact methods are confirmed.

Tip for accounting firms: register a firm email address in addition to the client’s, so notices reach someone who reads them.

What if I already have it enabled?

Check two things:

• That the email addresses still exist. A deactivated email address is the same as having no contact method.
• That someone checks the mailbox regularly. SAT considers whatever it drops there as notified.

The hard part for a firm: checking dozens of mailboxes

If you handle 20 or 30 RFCs, logging into the portal one by one to see if there is anything new is exactly the kind of task that gets forgotten. Clauhub Fiscal checks the Buzón Tributario of every connected RFC and lets you know when something new arrives, along with the tax status certificate and the compliance opinion. Discover Clauhub Fiscal

Frequently asked questions

Can I enable it with the password (CIEC)? Yes. The e.firma is another way to log in, but it is not required to enable it.

How much is the fine? From $3,850 to $11,540, depending on the conduct. The amounts are adjusted for inflation.

When do fines start? From January 1, 2027 for the cases whose penalty was deferred, under the fourth transitory article of the RMF 2026.