Oman 2026 E-Invoicing: OTA Publishes Draft Data Dictionary

Oman Tax Authority (OTA) announced that it will gradually roll out the national e-invoicing system starting in Q3 2026, specifically in August 2026. The first step in the process has already been taken by the OTA, which, in October this year, informed the first group of 100 largest taxable persons that they will be part of Phase 1 when the system goes live. 

As part of this preparation phase, the OTA also released a draft version of the e-invoicing Data Dictionary for public consultation and held two workshops with selected companies. These sessions provided needed clarifications on the planned e-invoicing rollout and allowed participants to ask questions regarding technical data requirements.

Main E-invoicing Data Dictionary Points

OTA clarified that e-invoicing will apply to all transaction types, including standard and zero-VAT-rated transactions, as well as supplies that are out of the scope of VAT. The system will cover all supply categories, including B2B, B2C, and B2G. Notably, OTA stated that issuing e-invoices for everyday consumer transactions is expected to be particularly difficult for sectors with high sales volumes. 

Additionally, OTA identified potential difficulties for businesses in B2B and B2G supply, including compliance with specific formats, securing customer approvals, and adjusting internal processes. Nonetheless, OTA underlined that taxable persons will need to follow its guidance closely, reassess their procedures and VAT positions, and ensure their ERP or billing systems can support the new requirements.

The Data Dictionary significantly expands the information required for e-invoices in Oman. Therefore, for standard e-invoices, businesses will need to include 53 mandatory data fields, with another 66 fields triggered only in specific circumstances. The printed version of standard e-invoices, referred to as a human-readable version, will require 46 essential fields. However, an additional 50 fields may be required if certain conditions are met.

OTA's draft outlines detailed business rules for eight core document types, covering everything from standard tax invoices to simplified versions, as well as standard and simplified prepayment documents and both debit and credit notes.

Regarding reporting timelines, OTA stated that e-invoices for B2B and B2G transactions must be generated through real-time integration with the approved service provider, meaning businesses must transmit invoice data instantly as transactions occur. For B2C supplies, OTA noted that further guidance is still expected, particularly on whether it will permit batch submissions or require a different reporting approach.

Conclusion

Even though further instructions, clarifications, and guidance are expected from OTA, businesses can still take specific steps to prepare for upcoming changes. Some of the most critical steps in this phase include comparing their current ERP and billing systems with the requirements set out in the Data Dictionary to identify gaps, and evaluating whether they are ready for real-time API connections with accredited service providers. 

Other preparatory actions include identifying any necessary system upgrades or external workarounds, and verifying VAT classifications and master data are accurate and up to date to ensure smooth implementation.

Source: KPMG, VATabout