Mexikos Steuererklärungssystem digitalisiert

Mexico’s Tax Administration Service (SAT) has transitioned to the new online platform for DIOT reports. The old desktop application is no longer accepted as of August 1, 2025.

Mexico’s tax authority, Servicio de Administración Tributaria (SAT), has successfully implemented a significant change in modernizing its tax filing systems. The new online platform for “Declaración Informativa de Operaciones con Terceros (DIOT)” reports, which detail transactions with third parties, is now mandatory.

Transition Process Completed – Only New Platform Accepted

IMPORTANT: As of July 31, 2025, the old desktop application (DEM 1.2.1) and .dec file format are no longer accepted. All taxpayers must now use the new online platform.

This change affects the monthly or semi-annual submission of DIOT reports, which contain details of Value Added Tax (VAT, or IVA in Spanish) transactions with suppliers. The regulation applies to both individuals (personas físicas) and legal entities (personas morales).

New System Features

SAT’s online platform offers users two different data entry options: direct data entry or bulk upload via .txt file format. This innovation simplifies the process by eliminating the need for external software.

Don’t Forget Submission Deadlines: According to article 4.5.1 of the 2025 Miscellaneous Fiscal Resolution (RMF), DIOT reports must be submitted no later than the last day of the month following the period in which the transactions took place. For August 2025 transactions, the deadline is September 30, 2025.