Invoicing EU Business Clients as an Autónomo: ROI and Reverse Charge

You work as an autónomo on Mallorca and you're about to invoice a business client somewhere else in the EU, say in Germany, France, or Ireland. Without an entry in the Registro de Operadores Intracomunitarios, the ROI, and without a VAT number for your client that's confirmed in the VIES system, you're not allowed to invoice net of Spanish IVA. Plenty of autónomos only find this out when their gestoría asks questions at the next Modelo 303, or when Hacienda comes back years later demanding the missing tax. This guide covers how to register for the ROI through Modelo 036, what a reverse charge invoice needs to look like, and where those transactions show up again on Modelo 303 and Modelo 349.

What the ROI is and why you need it

The ROI, the Registro de Operadores Intracomunitarios, is the Spanish tax authority's register for businesses and self-employed people who buy or sell goods and services across borders within the EU. Being registered is a precondition for issuing intra-EU invoices without Spanish IVA under the reverse charge mechanism.

Without that registration, Hacienda treats your client abroad like a domestic client. You then have to invoice with 21 percent Spanish IVA, even if the client holds a valid VAT number in their own country. This usually only comes to light when the client rejects the invoice, or when your gestoría asks at the quarterly close why an intra-EU transaction was booked with IVA on it.

How to register for the ROI

If you don't have Cl@ve or a Certificado digital, you can also book a Cita previa at an AEAT office, though waiting times are longer that way. A gestoría will usually handle the registration for 40 to 100 EUR, and knows which IAE activity code fits your case.

Getting the reverse charge invoice right

If your client's VAT number checks out in VIES and you're registered in the ROI yourself, you invoice net, with no IVA line. On the invoice, add the note "Intra-Community operation, reverse charge, Art. 196 of Directive 2006/112/EC" along with both tax numbers, yours and your client's.

Check the VIES number as close as possible to the invoice date and keep a screenshot of the lookup. If the client later loses their registration, that doesn't change an invoice that was correctly issued at the time, but without proof a later audit becomes far more work.

Modelo 303 and Modelo 349: where the transactions reappear

On Modelo 303, your quarterly IVA return, you report the exempt intra-EU supply in the fields set aside for it, even though no IVA is due. On top of that, Hacienda requires the summary declaration on Modelo 349, which lists every EU client individually with the amount invoiced.

Under the official instructions from the Agencia Tributaria, Modelo 349 is normally due monthly. If your intra-EU turnover stays under 50,000 EUR (excluding IVA) in the current quarter and the four preceding ones, you can file quarterly instead, within the first 20 days of the following month. Most autónomos with modest business abroad stay under that threshold and file quarterly, alongside Modelo 303.

Special cases: private clients, non-EU countries, and platforms

• For a private individual abroad, reverse charge doesn't apply, you invoice with Spanish IVA. The one exception is digital services above the EU-wide threshold of 10,000 EUR, where the One-Stop-Shop scheme applies instead.
• Clients in Switzerland or the UK sit outside the EU, and VIES only checks EU numbers anyway. For them the general place-of-supply rule applies: the service is deemed to be supplied where the client is based, so it's not taxable in Spain, and no ROI entry is needed for it.
• If you work through a platform like Upwork, you're usually invoicing the platform company itself, a business in a third country, not the end client directly. The same place-of-supply rule as for non-EU clients applies.

Do I need the ROI if my client abroad is a private individual? No. Reverse charge only applies between businesses. For a private individual, you invoice with Spanish IVA regardless of whether you're registered in the ROI.

If you switch between several of these cases, say a business client in one EU country alongside private customers, check which rule applies invoice by invoice, rather than relying on a rule of thumb you learned once.

Conclusion

Registering in the ROI through Modelo 036 and a checked VIES number are what let you invoice a business client elsewhere in the EU without Spanish IVA, under reverse charge. Those transactions then land on Modelo 303 and, usually quarterly, on Modelo 349. Private clients, non-EU clients, and platforms like Upwork each follow their own rules, and it's worth sorting out which applies before your first invoice, not once your gestoría or Hacienda comes asking. For more on invoicing as a self-employed worker, see the guide to invoicing in Spain; for the basics of registering, see the guide to becoming an autónomo in Spain.