Oman Introduces Mandatory E-Invoicing from April 2027

• Oman has amended its VAT Executive Regulations through Decision No. 189/2026, introducing mandatory structured electronic invoicing for VAT-registered businesses.
• Taxable persons with annual supplies exceeding OMR 5 million must comply from 1 April 2027, while those at or below the threshold must comply from 1 October 2027.
• E-invoices must be issued, transmitted and retained in an approved secure electronic format. Paper invoices, ordinary PDFs and invoice images sent by email will not qualify as electronic tax invoices under the new framework.

Source RTC

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The Oman Tax Authority has issued Decision No. 189/2026 amending the Executive Regulations of the VAT Law and establishing the legal framework for mandatory electronic invoicing.

The development was reported in the Oman Tax Alert : E-Invoicing framework, received on 21 August 2026. The alert states that taxable persons will progressively move from traditional invoices to approved and secured electronic invoices carrying unique invoice numbers.

The mandate will be implemented in two phases:

• 1 April 2027: taxable persons whose annual supplies exceed OMR 5 million;
• 1 October 2027: taxable persons whose annual supplies are OMR 5 million or less.

The official Oman News Agency confirms that all companies registered for VAT will be required to issue invoices electronically using the system approved by the Tax Authority. The invoices will use an approved XML format that allows systems to read, analyse and process invoice data automatically. For B2B transactions, invoices will be exchanged between the seller’s and buyer’s systems through service providers accredited by the Tax Authority. [omanobserver.om], [omannews.gov.om]

Paper invoices, PDF invoices and digital images sent by email will not be recognised as electronic tax invoices once the relevant mandate becomes applicable. This distinction is important because an invoice is not considered an e-invoice merely because it is created or delivered electronically. It must comply with the prescribed structured format and technical requirements. [omanobserver.om], [arabianbusiness.com], [omannews.gov.om]

The amended rules also require:

• a unique number for each electronic invoice;
• secure issuance through an electronic system;
• protection against hacking and unauthorised access;
• procedures for emergencies, system failures and technical interruptions;
• mechanisms for recovering lost data; and
• continued readability, integrity and verifiability throughout the retention period.

Tax and simplified tax invoices must be issued within the applicable statutory timeframe. The tax alert states that this is generally within a maximum of 15 days following the relevant triggering event. [omanobserver.om]

The Chairman of the Oman Tax Authority may grant a limited exemption following an application supported by acceptable grounds and documentation. According to the tax alert, an exemption is conditional on timely VAT return filing and payment. This should therefore be viewed as a restricted relief mechanism rather than a general postponement option.

The Tax Authority has selected 100 companies for a voluntary pilot scheduled to begin at the end of August 2026. According to the official announcement, the pilot is intended to test the system and assess readiness before mandatory implementation. [omanobserver.om], [omannews.gov.om]

Businesses should now determine which implementation date applies, review whether billing and ERP systems can generate the required structured invoice, assess connectivity with accredited service providers, and document security, archiving, continuity and data-recovery controls.

External sources

• Oman News Agency announcement on Decision No. 189/2026 [omannews.gov.om]
• Oman Observer overview of the phased mandatory regime [omanobserver.om]
• KPMG analysis of the amended VAT Executive Regulations [kpmg.com]
• Sovos — Oman Fawtara rollout timelines revised [sovos.com]
• e-Invoice.app — Oman puts its e-invoicing dates in law [e-invoice.app]
• VAT IT — Oman’s e-invoicing rollout changed [vatit.com]

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Other articles

• Mandatory e-invoicing becomes law in Oman under Decision No. 189/2026. Taxable persons must issue VAT invoices in an approved and secure electronic format, with unique invoice numbering and controls ensuring authenticity, integrity, and readability throughout the retention period. The rules also apply to simplified invoices and advance payments.
• A phased implementation timeline applies based on annual turnover. Businesses with annual supplies exceeding OMR 5 million must comply from 1 April 2027, while businesses with annual supplies of OMR 5 million or less have until 1 October 2027. Limited exemptions may be granted by the Tax Authority upon application and subject to strict conditions.
• Companies should begin preparations now. Key actions include assessing ERP and billing system readiness, monitoring the list of licensed e-invoicing service providers, implementing cybersecurity and business continuity controls, and ensuring invoices can be securely generated, stored, verified, and recovered when required.

Source Acquisory