E-Commerce Seller's Guide to UK VAT OSS, MOSS and Cross-Border Compliance

Online sellers who trade across borders face a patchwork of VAT rules that differ from country to country, and the UK's post-Brexit framework has added new layers of complexity. Whether you are a UK seller dispatching to EU customers, or a foreign seller dispatching into the UK, the One Stop Shop (OSS) scheme is central to how you account for VAT. This guide explains the place-of-supply rules, the OSS mechanism, the UK's own import VAT regime, and the practical steps a seller needs to take to stay compliant.

Place of supply: where VAT is charged

The fundamental rule is that VAT is charged in the country where the supply "takes place". For cross-border e-commerce:

• B2C physical goods (distance sales). After Brexit, the place of supply for goods sold by a UK seller to an EU consumer is the consumer's country — meaning the UK seller must charge EU VAT at the local rate. Similarly, an EU seller selling to a UK consumer must charge UK VAT at 20%.
• B2B physical goods. For business-to-business sales, reverse charge usually applies: the seller invoices without VAT, and the buyer accounts for VAT in their own country.
• B2C digital services. The place of supply for digital services (e-books, software downloads, streaming, SaaS) sold to EU consumers is the consumer's country. The same applies to services sold into the UK.

The One Stop Shop (OSS) scheme

The EU One Stop Shop, introduced in July 2021, allows a non-EU seller (including a UK seller) to register for OSS in a single EU member state and account for VAT on all B2C EU sales from that one registration, rather than registering in every country individually. A UK seller using OSS registers in the country where it has the greatest EU sales volume, files a single quarterly OSS return listing total sales per EU country, and remits the VAT in one payment to the registering member state, which distributes it to the relevant countries.

OSS is voluntary but practically essential for any UK seller with customers in more than two or three EU member states. Without it, the seller would need to register for VAT in every destination country — quickly unmanageable.

Non-Union MOSS and the old UK regime

Before OSS, the Mini One Stop Shop (MOSS) existed for digital services only. After Brexit, UK sellers lost access to Union MOSS and moved to Non-Union MOSS. With the introduction of OSS in 2021, Non-Union MOSS was absorbed into the OSS scheme for most sellers. New sellers selling digital services into the EU from the UK register for OSS directly.

UK import VAT for goods sold into the UK

For goods dispatched from outside the UK to UK consumers, the seller (or the online marketplace if it is the deemed supplier) is responsible for collecting UK VAT at the point of sale. Under the UK's "low-value goods" rules, consignments valued at £135 or less have VAT collected at the point of sale, not at the border. A seller shipping a £50 item from the EU or US to a UK consumer must register for UK VAT and charge 20%, unless the sale is through an online marketplace that has taken on the VAT obligation.

Practical steps for compliance

1. Identify your place of supply for each product and customer type. Physical goods to consumers: destination country. Digital services to consumers: destination country. B2B sales: reverse charge.
2. Register for OSS if you sell B2C to EU consumers from outside the EU, choosing the registration country based on greatest sales volume.
3. If selling into the UK from outside, register for UK VAT and account for VAT on goods valued at £135 or less at the point of sale.
4. File quarterly OSS returns listing total B2C sales per EU member state. Keep records for 10 years.
5. Verify VAT numbers on VIES for EU numbers and HMRC for UK numbers — an invalid number is a compliance risk for both you and your counterparty.
6. Keep invoices compliant. The OSS return is a summary; you still need proper VAT invoices for each sale, showing the place of supply and rate charged.

VAT on cross-border e-commerce is not a DIY area once your sales volume grows beyond a handful of countries. If you sell in more than three EU member states or deal in digital services with complex place-of-supply questions, a VAT advisor familiar with OSS is worth the cost — discovering an error years later and facing backdated assessments in multiple jurisdictions is far more expensive.