According to art 194 of the VAT Directive, Member States may implement an optional reverse charge on supplies made by non-established businesses. Spain has introduced an extended version of this reverse charge.
Where a non-established supplier sells goods to a taxable person, domestic reverse charge applies. It is not relevant if the supplier is registered or not. Regarding the customer, it is not relevant if it is established or VAT registered. Even when the customer is not VAT registered, reverse charge applies, hence requiring this customer to register and account for VAT.
Not established in Spain
(irrelevant if the supplier is registered or not for VAT)
(irrelevant if the customer is established or VAT registered)
All supplies of goods
Supplies of services located in Spain (exceptions to the B2B rule).