11 September 2026

US-Spain Inheritance Tax: Why There's No Treaty Protecting Your Estate From Double Taxation

If you own property in Spain, your estate can face two tax bills when you die: Spanish inheritance tax on the property itself, and, if your worldwide estate is large enough, US federal estate tax on that same asset. No treaty prevents the overlap — the 1990 US-Spain tax agreement covers income tax only. A US credit can offset part of the double hit, but rarely all of it.

A note before you dive in: estate and tax rules shift — sometimes quickly, and estate tax law in particular has been in flux in the US. What follows reflects our latest research, but you should always confirm the current specifics with a cross-border estate planning attorney or CPA before acting on them.

The Treaty That Doesn't Cover This

American buyers researching Spanish property tax often run into the 1990 US-Spain income tax treaty and assume it handles everything cross-border, including what happens to the property when they die. It doesn't. The Convention signed in Madrid in February 1990 governs how dividends, interest, capital gains, pensions, and other income are taxed between the two countries — it has nothing to say about estate or inheritance tax, and it was never meant to.

The US does maintain separate estate and gift tax treaties with a short list of countries — the UK, France, Germany, Italy, Japan, Australia, Ireland, and a handful of others — that specifically address how the two governments divide taxing rights when someone dies owning cross-border assets. Spain isn't on that list, and no negotiation toward one is underway. That absence is confirmed independently by Spanish and US practitioners writing for cross-border clients: there is no bilateral US-Spain estate and inheritance tax treaty (source: Sucesio), and the existing 1990 agreement covers income tax but not inheritance or estate tax (source: Bufete Padilla).

The Myth Worth Correcting

You'll sometimes see the claim, repeated on forums and even on some professional-looking guides, that a "1990 US-Spain estate tax treaty" exists, or that the income tax treaty extends to inheritance because it's a similar-sounding 1990 document. It doesn't hold up. There's one 1990 treaty between the two countries, it's about income tax, and it stops there — a fact confirmed by both the treaty text itself and by the estate planning firms that deal with US clients inheriting Spanish property every year. If a source tells you your heirs are automatically protected from double taxation because of "the treaty," that's the moment to ask which treaty, specifically, and to get a second opinion.

What US Federal Estate Tax Looks Like From Here

The US estate tax follows citizens and long-term residents wherever they live and wherever their property sits — it applies to your worldwide estate, not just US-based assets, so a home in Spain counts toward the total regardless of where you spend your time. For 2026, the federal exemption sits at $15 million per person, with amounts above that taxed at rates up to 40% (as of August 2026). That figure is worth pausing on, because for the past several years estate planners had been telling clients to expect the exemption to roughly halve — down to somewhere near $7 million — when the Tax Cuts and Jobs Act provisions were set to expire at the end of 2025. That sunset didn't happen. The One Big Beautiful Bill Act, signed into law in July 2025, raised the exemption to $15 million and made it permanent, indexed for inflation from 2027 onward. Treat the exact figure as directional rather than final — exemption amounts get indexed and occasionally revised by Congress, and where your specific estate sits relative to the threshold is exactly the kind of number a CPA should confirm from primary IRS guidance before you make any decision based on it.

Practically, this means most American buyers looking at property on the Costa del Sol fall well under the federal threshold and won't owe US estate tax at all. The exposure concentrates among buyers with larger overall estates — where the Spanish property is one piece of a portfolio that, combined, crosses $15 million (or $30 million for a married couple using both exemptions). If that's your situation, the Spanish property doesn't create the US tax liability on its own, but it does add to the total that determines whether the liability exists.

What Spanish Inheritance Tax Looks Like on the Ground

Spain's approach runs on a different logic entirely. The Impuesto de Sucesiones y Donaciones (ISD) taxes assets located in Spain regardless of who inherits them or where that person lives — an American heir with no other connection to Spain still owes it on Spanish property they inherit. Spain also delegates much of the rate-setting and relief structure to its seventeen autonomous communities, so the actual bill depends heavily on which region the property sits in.

For the Costa del Sol — Málaga province, within Andalucía — the regional rules are notably generous toward close family. Spouses, children, and parents (the tax code's Group I and II) deduct €1,000,000 per heir from the taxable base before any tax is calculated, and a 99% bonification then applies to whatever tax remains on top of that (as of August 2026) (source: Real Estate Andalusia). A primary residence inherited by close family gets a further 99% reduction if the heir keeps the property for three years. Run the numbers on a mid-market Costa del Sol home passing to a spouse or child, and the Spanish tax due is frequently close to zero — though the return still has to be filed to claim it.

It's worth knowing this isn't automatically available to non-EU nationals — it used to not be. Until 2018, Spain applied its more generous regional rules only to EU/EEA residents, leaving non-residents from outside the bloc stuck with the less favorable national scale. The Spanish Supreme Court ended that distinction in 2018, ruling it violated the EU principle of free movement of capital, and extended the regional benefits — including Andalucía's — to heirs anywhere in the world, Americans included (source: International Tax Review). The generous end of Spanish inheritance tax, in other words, is now genuinely open to American heirs, not just Spanish or EU ones.

The relief is narrower outside close family. Siblings, unmarried partners, and unrelated heirs fall into Groups III and IV, where Andalucía's reductions are minimal or absent and the national rate scale applies in fuller force. If your Spanish property is going to a partner you're not married to, or to someone outside the immediate family, the tax exposure looks very different — and that's a conversation worth having with a Spanish lawyer well before it becomes relevant. It also intersects with Spain's forced-heirship rules, which we cover separately in (estate-planning-inheritance-spain-americans).

The Clock: Modelo 650

Once someone dies owning Spanish assets, the heirs have six months from the date of death to file Modelo 650, the Spanish inheritance tax self-assessment, with the tax authority for the relevant region (source: Agencia Tributaria). A single extension of another six months is available, but the request has to go in during the first five months of that initial window — file for the extension in month six and it's too late. The extension isn't free, either: interest accrues on any tax owed from the end of the original six-month period until the return is actually filed. For an American family already navigating probate, a foreign language, and grief, six months moves faster than it sounds, which is part of why lining up a Spanish lawyer well before it's needed matters.

Can the Foreign Tax Credit Fix the Overlap?

There is a mechanism for relief, but it's narrower than a treaty and worth understanding on its own terms — it's not the same foreign tax credit that applies to income tax. Under Internal Revenue Code Section 2014, a US estate can claim a credit against federal estate tax for death taxes actually paid to a foreign country on the same property, certified on Form 706-CE and calculated on Schedule P of Form 706 (source: IRS). The credit is capped at the smaller of two amounts: the foreign tax attributable to that specific property, or the US estate tax attributable to it — so it offsets the overlap on that asset, not the estate as a whole.

In practice, the two systems rarely collide as hard as the "double taxation" framing suggests. Estates under the $15 million US threshold owe no federal estate tax regardless of what Spain charges, so there's nothing to credit against. Estates that do clear the threshold, with Spanish property passing to close family in Andalucía, may find the Spanish side is close to zero after the regional reductions — again leaving little to credit, but also little actually paid twice. The credit earns its keep in the middle ground: larger estates, heirs outside the close-family groups, or property in regions with less generous relief than Andalucía's. Getting the credit right is a matter for a CPA who has filed Schedule P before — it's not a box most general tax preparers check often.

Where This Fits in the Bigger Picture

Estate tax is one piece of a wider planning question that also includes how Spanish forced-heirship rules interact with a US will, and whether you can elect your home-state law to govern the succession instead (our guide on (estate-planning-inheritance-spain-americans) covers that ground). It's separate again from the annual taxes that apply while you're alive and simply own the property, covered in (property-taxes-spain-american-owners), and from the income tax treaty mechanics discussed in (us-spain-tax-treaty-double-taxation). None of these substitute for the others — a buyer doing this properly ends up coordinating a Spanish lawyer and a US cross-border CPA on all three at once, ideally before the purchase closes rather than after.

None of this is a reason to avoid buying on the Costa del Sol — most American buyers' estates never approach the federal threshold, and the assets that do get taxed in Spain, for close family in Andalucía, are often taxed lightly. It's a reason to plan with eyes open rather than assume a treaty is doing work it isn't. At Luumare Estate we work alongside a network of cross-border lawyers and tax advisors for exactly this reason — structuring how a property is held and who it passes to is part of the conversation from the first viewing, not an afterthought after closing. See our services page for how we coordinate that, or reach out if you'd like to talk through your specific situation before you buy.