VAT Number Check Guide Reviewed 1 August 2026

VAT Number Check Ireland: VIES Validation Guide

How to check an Irish or EU VAT number through VIES, understand the result and keep evidence for cross-border VAT records.

Quick answer

  • Use the European Commission VIES service to validate an EU VAT number for intra-EU trade.
  • Select the customer country and enter the number without guessing or changing its characters.
  • A valid VIES result supports the VAT-number check but does not prove every other condition for zero-rating or reverse charge.
  • Save the date, result and reference or screenshot with the transaction records.
Calculator

VAT Calculator

Open this Irish calculator to test your own numbers and compare the result with the guide.

FreeIrish planning tool EstimateFor guidance only 2026Ireland-focused
Use VAT Calculator
On this page
  1. What does VIES check?
  2. How to validate a VAT number step by step
  3. Irish VAT number, tax number and CRO number
  4. Why a VAT-number check may fail

What does VIES check?

VIES checks whether a VAT number is recorded as valid for intra-EU transactions. It is the appropriate public check when an Irish business needs to validate an EU customer’s VAT status before applying cross-border VAT treatment.

Important limit: a valid number is only one part of the evidence. The supplier may also need to verify the customer’s identity, the transaction, where goods moved or where services were supplied, and the invoice wording.

How to validate a VAT number step by step

  1. Ask the customer for its legal name, address, country and VAT number.
  2. Open the official VIES VAT-number validation service.
  3. Select the Member State that issued the number.
  4. Enter the VAT number carefully, normally without adding the country prefix twice.
  5. If available, enter your own VAT number so the enquiry can be linked to the supplier.
  6. Review whether the result is valid and whether returned identity details match the customer.
  7. Save the result, date and reference with the invoice and transport or service evidence.

Irish businesses approved for intra-EU VAT registration are automatically registered for VIES. A domestic-only VAT registration may therefore need to be updated before intra-EU trading begins.

Irish VAT number, tax number and CRO number

An Irish VAT number is a tax identifier and normally begins with the country code IE when used for EU trade. It is not the same thing as a CRO company number. Formatting can vary because older and newer Irish identifiers do not all look identical, so use the official validation result instead of relying only on visual format.

Identifier What it identifies Best check
VAT number VAT registration and, where applicable, intra-EU VAT status VIES for EU validation; Revenue records for your own registration
CRO number A company or registered business record Companies Registration Office
Tax reference number A taxpayer or tax registration Revenue correspondence or ROS

Why a VAT-number check may fail

  • The country or number was entered incorrectly.
  • The registration is domestic-only and not active for intra-EU trade.
  • The registration is new and has not yet appeared in the relevant system.
  • The VAT number was cancelled or is not valid for the transaction date.
  • The VIES service or a national database is temporarily unavailable.

Recheck the number and country, ask the customer to confirm its legal details and registration status, and retain the failed result. Do not change a number until it produces a valid response or assume that a company name alone proves VAT registration.

Frequently asked questions

How do I check an Irish VAT number?

Use the official VIES service for intra-EU validation, select Ireland and enter the number carefully. Save the result with the transaction records.

What does a valid VIES result prove?

It confirms that the number is recorded as valid for intra-EU VAT purposes at the time of the check. It does not prove all other conditions for zero-rating or reverse charge.

Why is a VAT number invalid on VIES?

It may be mistyped, domestic-only, newly registered, cancelled or affected by a temporary service problem. Recheck the details and ask the customer to confirm its status.

Is an Irish VAT number the same as a company number?

No. The VAT number is a tax identifier, while the CRO number identifies a company or registered business record.

Should I keep evidence of a VAT-number check?

Yes. Keep the date, result and any enquiry reference or screenshot with the invoice and other evidence supporting the transaction.

Sources & references

Back to VAT Ireland
Reverse Charge VAT Ireland 2026: Rules & Examples Irish reverse-charge VAT explained for services received from abroad, intra-EU trade, construction, invoices and VAT3 self-accounting. VAT Invoice Requirements Ireland: Quotes, Receipts & Invoices Irish VAT invoice requirements, issue dates, full and simplified invoices, quote-to-invoice examples, corrections and reverse-charge wording. VAT Registration Ireland 2026: Thresholds & How to Register Irish VAT registration thresholds for services, goods and cross-border activity, plus voluntary registration, sole traders and the ROS application process.

Related calculators

Use these tools for the numbers behind this guide.

VAT Add or remove VAT
Scroll to Top