IOSS EU Intermediaries 2026: Which Is Right for UK Sellers?
As a UK seller based in Great Britain, you cannot register for IOSS directly. You must appoint an EU-established intermediary — a business registered in an EU member state that registers on your behalf, files your monthly returns, makes VAT payments to EU tax authorities, and is jointly and severally liable for any VAT you owe.
For the full side-by-side comparison of IOSS intermediary providers — covering EAS Project, SimplyVAT, AVASK, Hellotax, Cross Border VAT, and Avalara, with pricing, integrations, and who each one suits — see the dedicated guide:
IOSS Intermediary Comparison — All Non-EU Sellers
Why UK GB Sellers Cannot Register Directly
Section titled “Why UK GB Sellers Cannot Register Directly”IOSS registrations are administered through EU member state tax portals. Non-EU businesses — including UK businesses in Great Britain — cannot access these portals directly. An EU-established intermediary acts as the legal bridge: they hold the IOSS registration in an EU country, and you operate under their registration as a “represented taxpayer.”
This is not optional or a workaround. It is the legal structure of IOSS for non-EU sellers. The intermediary takes on legal liability for the VAT, which is why they charge a monthly fee and require ongoing access to your sales data.
Northern Ireland Exception
Section titled “Northern Ireland Exception”If your business is based in Northern Ireland, you do not need a private EU intermediary. Under the Windsor Framework, NI businesses remain within the EU’s VAT system for goods and can register for IOSS directly through HMRC.
From 1 April 2026, HMRC also accepts NI-based intermediary registrations — meaning NI businesses can act as IOSS intermediaries on behalf of other non-EU sellers, not just for their own registrations.
If you are in Northern Ireland: contact HMRC’s VAT helpline or use HMRC Online Services to start your IOSS registration. The €40–300/month intermediary cost that applies to GB sellers does not apply to you.
UK-Specific Considerations When Choosing a Provider
Section titled “UK-Specific Considerations When Choosing a Provider”Beyond the generic factors covered in the full comparison (pricing, integrations, contract terms), UK sellers should also consider:
English-language support: most major intermediaries offer English-language support, but confirm this upfront, especially for providers registered in non-English-speaking member states. SimplyVAT and Cross Border VAT are both founded and primarily operated from the UK and offer native English support.
Country of your IOSS registration: your IOSS number is tied to the country where your intermediary is registered. Ireland is the most common choice for UK sellers, partly because of English-language support from Revenue.ie. This makes no practical difference to how IOSS works across the 27 EU countries — it is purely an administrative choice.
Switching process: switching intermediaries means deregistering your current IOSS number and receiving a new one. You must update this in your store, with your carrier, and in your customs declarations. If you are locked into a 12-month contract (SimplyVAT, for example) and want to leave, you may face exit fees. Factor this in before signing.