Mexico’s tax authority, the Servicio de Administración Tributaria (SAT), has confirmed that all individuals and legal entities with active tax obligations must activate their Buzón Tributario—the official digital tax mailbox—by December 31, 2025. Starting January 1, 2026, failure to comply will result in financial penalties, even for those without outstanding debts.
The Buzón Tributario serves as the SAT’s primary channel for delivering legally binding notifications, administrative resolutions, and compliance requests. While the requirement to activate the mailbox has existed since 2020, enforcement has so far relied on voluntary compliance. The upcoming shift introduces sanctions for non-compliance, signaling a move from encouragement to compulsion in Mexico’s digital tax administration.
Taxpayers must register a valid email address and mobile phone number through the SAT portal and confirm both within 72 hours to complete activation. Without this validation, the mailbox is not considered active. The SAT emphasizes that this digital channel enhances legal certainty, reduces administrative burdens, and facilitates timely access to fiscal benefits and compliance programs.
Missing official notifications—even unknowingly—does not exempt taxpayers from legal responsibility.
Not all taxpayers are subject to the requirement. Exemptions apply to individuals with suspended or cancelled registrations in the Federal Taxpayer Registry (RFC), those without economic activity or fiscal obligations, and salaried workers who earned less than MXN 400,000 in the previous fiscal year. However, for all others with active RFCs and tax responsibilities, activation is mandatory.
The policy forms part of a broader effort by Mexican authorities to modernize tax oversight through digital tools. By centralizing communication and reducing reliance on physical notifications or in-person visits, the SAT aims to streamline enforcement and reduce evasion risks.
Still, concerns remain about the policy’s impact on segments of the population with limited access to digital infrastructure or low levels of digital literacy. Small businesses and informal workers may face particular challenges in navigating the activation process or maintaining updated contact information. Questions about data security and equitable access also persist as more administrative functions move online.
The SAT has made clear that no extensions will be granted beyond the December 2025 deadline. Taxpayers are urged not to delay activation, as missing official notifications—even unknowingly—does not exempt them from legal responsibility.
