If you are a non-resident: three obligations apply to your sale
The 3% withholding
The buyer retains 3% of the sale price and pays it to the Spanish tax authority. This does not apply to resident sellers who present the correct certificate. For non-residents, it is not your final tax bill: it is a deposit against what you may owe. If your actual liability is lower, you are entitled to a refund, but the claim has a four-month deadline. Miss it and the money stays with Hacienda. We file and follow up until the refund lands.
Capital gains tax (Modelo 210)
Non-residents declare the gain through Modelo 210, not through the annual income tax return. The capital gains tax rate on Spanish property is 19% for all non-residents, regardless of country of origin. The taxable gain is the sale price minus the purchase price and allowable costs: legal fees, notary, agency commissions, improvements. Most non-resident sellers never claim these deductions. Every allowable cost reduces your bill.
The plusvalía municipal
A local tax on the increase in land value, paid to the town hall. Since 2021 it cannot legally exceed the actual gain on the land, but town halls don't apply this automatically. We check it every time.