Intra-EU VAT: how to buy and sell across the EU without surprises (ROI, Form 349 and self-invoicing)

When a small business or self-employed professional starts buying from or selling to customers and suppliers in other EU countries, VAT stops working the way it does domestically. Three pieces suddenly matter, and getting them wrong either triggers problems in an audit or — more commonly — means paying VAT twice out of sheer unfamiliarity: registration in the Register of Intra-Community Operators (ROI), the reverse charge mechanism with its corresponding self-assessment, and Form 349. Let’s take them one at a time.

ROI registration: the first step before invoicing the EU

The ROI is a Spanish Tax Agency register that businesses must join before carrying out regular intra-Community transactions. Without ROI registration, your Spanish VAT number won’t show as valid in VIES (the VAT Information Exchange System), which is exactly what a supplier or customer in another EU country checks before invoicing you without VAT. Registration is requested via Form 036, ticking the box for intra-Community transactions, and it typically takes a few days for the Tax Agency to process and activate your VAT number in VIES. A common mistake is starting to buy from the EU and only discovering, once the goods have already arrived, that the supplier charged their own country’s VAT because your Spanish VAT number wasn’t yet showing as valid — in that case you have to request a corrected invoice, and in the meantime that foreign VAT isn’t deductible in Spain. The practical takeaway: if you expect to trade with the EU, apply for ROI registration well in advance, before your first transaction, and check your own VAT number in VIES before invoicing a new EU customer.

Reverse charge and self-assessment: why there’s no VAT on the purchase invoice

In an intra-Community acquisition of goods between businesses, the supplier in the other EU country invoices without VAT (the transaction is exempt at origin), and it falls to the Spanish buyer to self-assess the VAT that would apply in Spain, as if they were the one selling. This is the reverse charge mechanism: the recipient, not the issuer, accounts for the tax. In practice, the buyer records both input VAT and output VAT for the same amount, at the Spanish rate for that good or service, in the same return. If the business is entitled to full VAT deduction, the cash effect is neutral — it’s recorded and offset at the same time. The mistake SMEs commonly make when they start importing or exporting within the EU is treating these invoices as if they carried ordinary input VAT, without recording the self-charged output VAT, or simply forgetting to declare it because “the invoice has no VAT on it.” Both lead to mismatches in Form 303 and can trigger information requests, since the Tax Agency cross-checks these transactions against data received from other EU countries.

Form 349: the return that exposes any mismatch

Form 349 is an informational return (no tax is due) that lists all intra-Community supplies and acquisitions of goods and services, identifying each customer or supplier by their VAT number. Its frequency depends on transaction volume — it can be monthly, quarterly, or even annual for very low amounts — and businesses need to watch out, since the required frequency changes if certain thresholds are exceeded during the year. The data reported in Form 349 is cross-checked against what tax authorities in other member states report through VIES, so any discrepancy between what the foreign supplier declares and what the Spanish buyer declares usually ends in an information request. The most typical errors: not filing Form 349 because “Form 303 already covers it” (they are separate, complementary returns), misclassifying the type of transaction (supply of goods, acquisition, or provision of services), or mismatching the reporting period between the quarter of accrual and the quarter in which the return is actually filed.

Intra-EU VAT isn’t complicated once you understand the mechanism, but it penalizes with interest and information requests anyone who improvises. At Zythos Business, we guide self-employed professionals and SMEs from their first ROI registration through to the coordinated filing of Forms 303 and 349, making sure every intra-Community invoice is properly classified and self-assessed before it becomes a problem with the Tax Agency.