IOSS Intermediary: A 2026 Guide for Non-EU Sellers

An IOSS intermediary is an EU-established taxable person who registers a non-EU seller for the Import One-Stop Shop, files the monthly IOSS returns, pays the VAT to the tax authority, and carries joint and several liability for VAT the seller fails to pay. Non-EU sellers can't use IOSS without one.

If your business sits outside the EU, you can't get an IOSS number on your own. You have to appoint somebody inside the EU to hold it for you, and that person becomes liable for your VAT alongside you.

We’ve put together this guide as to what the role actually involves, where the liability sits, and the questions worth asking before appointing an intermediary to handle your EU VAT.

How to choose an IOSS intermediary

The market runs from automated platforms to regulated accountancy firms, and the price gap between them can be significant. Since you're choosing who carries liability for your EU VAT, price shouldn’t be the biggest differentiator when compliance and penalties are at stake. Instead you should be asking:

Is the intermediary regulated, and by whom? A firm answerable to a professional body has something to lose if your filings are wrong. Ask for the regulator and the registration number, then check it.

Do they hold the intermediary registration themselves, or subcontract it? Some providers resell another company's intermediary status. This can be an issue when there's a problem and you find out your contract is with someone who isn't actually the intermediary.

Who prepares the return? Software that maps your sales data is fine. A qualified accountant reviewing it before submission is better, particularly in your first few months when classification errors are most likely.

Can you reach a named person? Compliance questions rarely arrive at a convenient moment. Find out whether you get an account and a ticket queue, or a person who knows your business.

What happens if you leave? Ask about deregistration, the handover of your ten years of records, and notice periods. Providers who make this awkward tend to be relying on it.

How are they handling 2028? A provider with no view on the Customs Data Hub or the end of the €150 threshold isn't watching the scheme closely enough to be useful to you.

Why non-EU sellers register through Ireland for IOSS

Any of the 27 member states can host an IOSS registration, and the scheme works the same in all of them. What differs is the experience of dealing with the tax authority behind it.

Ireland is English-speaking, which removes translation from every filing, every query and every piece of correspondence with Revenue. It has a tax administration used to dealing with foreign owned businesses, because a large share of the country's corporate base is exactly that. And for UK sellers in particular, an Irish registration keeps EU market access running through the nearest jurisdiction with the shortest cultural and legal distance from home. We've written about how UK retailers are using that route in our Irish Bridge case study.

Nathan Trust acts as IOSS intermediary for sellers in the UK, the US, India, China and across the world. We're a Chartered Accountants Ireland regulated firm and have been advising internationally owned Irish businesses since 1999. If you want the mechanics of getting registered rather than the role itself, our IOSS registration guide covers the process step by step.

Appointing Nathan Trust as your IOSS Intermediary

We register your company for IOSS in Ireland, hold the intermediary appointment ourselves, and file your monthly returns. You get a personal Chartered Tax Advisor rather than submitting a ticket to a support queue. With Nathan Trust you're forming a partnership that ensures your IOSS filings are compliant and ensure smooth trading with the EU.

Frequently Asked Questions:

Do I need an IOSS intermediary if I'm a US seller?

Yes. The US has no VAT mutual assistance agreement with the EU, so a US-established business can't register for IOSS directly. You'll need an EU-established intermediary to hold the registration and file on your behalf.

Do UK sellers need an IOSS intermediary?

Yes, in almost all cases. Since Brexit the UK is a third country for EU VAT purposes and has no mutual assistance agreement. A UK business with no EU establishment needs an intermediary to use the scheme. Nathan Trust offers IOSS intermediary services for UK sellers.

Can I register for IOSS without an intermediary?

Only if your business is established in the EU, or in Norway for goods dispatched from Norway. Every other non-EU seller has to appoint one.

What's the difference between an IOSS number and an intermediary number?

Your IOSS VAT identification number starts with IM and goes on your customs declarations. The intermediary's own identification number starts with IN, isn't a VAT number, and identifies the intermediary to the tax authority. One intermediary holds many IM numbers, one per client.

Is the IOSS intermediary liable for my VAT?

Yes. Under Irish Revenue's position the intermediary can be held jointly and severally liable with the supplier for VAT that goes unpaid. That's the defining feature of the role.

How long does IOSS registration take?

Through an Irish intermediary, plan for around four weeks, though timelines with any tax authority can run longer. Providers quoting same-day numbers are usually registering you in a jurisdiction with a lighter review process, which is worth understanding before you commit.

Can IOSS be used for B2B sales?

No. IOSS is a business-to-consumer scheme. Cross-border B2B supplies are handled under different VAT rules, and any provider suggesting otherwise is worth a second look.

What if my consignment is worth more than €150?

IOSS doesn't apply. Normal import VAT and customs procedures kick in, and VAT is collected at the border. You can still offer a delivered-duty-paid option to your customer through your carrier, it just sits outside the IOSS return.

Does IOSS work if I store stock in the EU?

No. IOSS covers goods imported from outside the EU at the point of sale. Stock already held in an EU warehouse needs local VAT registration or the OSS scheme.

Do I still need an intermediary after the 2028 customs reform?

The intermediary requirement for non-EU sellers isn't being removed. What changes in July 2028 is the scheme around it, with the €150 threshold abolished and the Customs Data Hub taking over import processing.