401(k) vs IRA vs Roth IRA in Spain: Which US Retirement Account Gets Taxed Worst?
401(k), Traditional IRA or Roth IRA: which US retirement account gets taxed worst once you become a Spanish tax resident? A clear side-by-side comparison ranking all three from worst to best, three worked numerical examples and a pre-move checklist to protect your savings before you land in Spain.
Jacob Salama
9/16/202611 min read
If you are an American planning a move to Spain, you have probably asked yourself some version of this question: "I have a 401(k), a Traditional IRA and a Roth IRA. Which one is going to hurt the most once I become a Spanish tax resident?"
It is exactly the right question to ask, and the answer surprises almost everyone. The account that is the most tax-efficient in the United States — the Roth IRA — is, as of 2026, the one that Spain treats worst. And the accounts Americans often worry about most, the 401(k) and the Traditional IRA, at least behave predictably under the US–Spain tax treaty.
In this article I compare the three vehicles systematically for a Spanish tax resident, rank them from worst to best, walk through three numerical scenarios, and give you a checklist of decisions to make in the year before you move. Because that is the real headline: most of the planning value is lost the day you become a Spanish tax resident.
How does Spain tax a 401(k) and a Traditional IRA?
Spain treats distributions from a 401(k) and from a Traditional IRA essentially the same way: as pension income, taxed in the general base of Spanish personal income tax (IRPF) at progressive rates that, depending on your region, reach roughly 45%–47% at the top as of 2026.
The logic is straightforward. Both accounts were funded with pre-tax dollars. Neither you nor the IRS ever paid income tax on the contributions or the growth. So when the money finally comes out, Spain — as your country of residence under the treaty — taxes the distribution as deferred employment income, i.e. a pension.
Key features of this regime:
The whole distribution is generally taxable, not just the growth, because contributions were pre-tax.
It lands in the general base, alongside salary and Spanish pensions, at progressive rates (roughly 19% to 45%–47%), not in the savings base at 19%–30%.
Timing is everything. A slow, steady drawdown of, say, $40,000 a year is taxed at moderate average rates. A single $500,000 lump sum in one tax year is a fiscal catastrophe, pushing most of it into the top brackets.
I explain the treaty mechanics of the 401(k) in detail in how a 401(k) is taxed in Spain under the tax agreement with the USA, and the specific quirks of IRAs — including RMDs and rollovers — in Traditional IRA in Spain: how distributions, RMDs and rollovers are taxed.
Is there any difference between the 401(k) and the Traditional IRA in Spain?
For distribution taxation, very little. Both end up in the general base as pension income. The practical differences are elsewhere:
Rollovers. A direct 401(k)-to-IRA rollover done while you are already a Spanish resident is a grey area: the safest reading is that a properly executed trustee-to-trustee rollover is not a taxable distribution, but the Spanish tax agency (AEAT) has no formal published doctrine blessing every variant. Doing the rollover before you move removes the question entirely.
Withdrawal flexibility. IRAs generally allow more flexible partial withdrawals than some employer 401(k) plans, which matters when you are trying to smooth income across Spanish tax years.
Required Minimum Distributions (RMDs). Both are subject to RMDs (currently from age 73 for most people, moving to 75 for younger cohorts under SECURE 2.0). Once RMDs start, you lose control over minimum timing — Spain will tax whatever the IRS forces out.
How does Spain tax a Roth IRA — and why is it the worst?
Here is the part that genuinely upsets people. In the United States, a qualified Roth IRA distribution is completely tax-free: you paid tax on the contributions going in, so everything — contributions and decades of growth — comes out untouched.
Spain does not recognise that tax-free status. As of 2026, Spanish law has no category for the Roth IRA. It is not a Spanish pension plan, and the US–Spain treaty does not force Spain to replicate the US exemption. So Spain applies its own general rules, and the prevailing technical position is:
Return of your original contributions (your basis) is not income — recovering your own after-tax capital is not a taxable event.
The growth — everything above your contributions — is taxable, generally as investment income in the savings base at 19% to 30% as of 2026.
Depending on how the account and the distribution are characterised, there is a less favourable alternative reading (annuity/pension treatment), which is precisely why documentation of your contribution basis matters so much.
Think about what that means for a long-held Roth. If Grace contributed $150,000 over twenty years and the account is now worth $600,000, then $450,000 of "US tax-free" money becomes taxable in Spain at up to 30%. That is potentially $120,000+ of Spanish tax on money the IRS would never have touched — and, unlike a 401(k) distribution, there is usually no US tax paid on it, so there is nothing to credit against the Spanish bill. The Spanish tax is a pure add-on.
That is why, counterintuitively, the Roth IRA is the account most damaged by a move to Spain: it goes from 0% (US) to 19%–30% (Spain) on all accumulated growth, with no offsetting credit. The 401(k) merely swaps US tax for Spanish tax; the Roth acquires a tax that did not exist before.
What should you liquidate before becoming a Spanish tax resident?
This is the highest-value planning question, and the answer follows directly from the analysis above.
Priority one: take qualified Roth distributions before you move
If you are over 59½ and the account has been open five years, your Roth distributions are qualified and 100% tax-free in the US. Take them before you become a Spanish tax resident and no country taxes them — ever. Wait until after, and Spain taxes all the growth at up to 30%. There is no other single decision in US–Spain retirement planning with a bigger and more certain payoff.
If you are under 59½, full liquidation may trigger US penalties on the earnings, and the calculation becomes a genuine trade-off that deserves professional modelling. But at minimum, withdrawing your contributions (always penalty-free and tax-free in the US) before the move simplifies your Spanish position enormously.
Priority two: consider lump sums or Roth conversions in your last non-resident year
For the 401(k) and Traditional IRA, the money will be taxed somewhere — the question is where and at what rate. In your last full year as a non-resident of Spain:
A large distribution or Roth conversion is taxed only by the US, at US federal rates (and state rates, unless you have already left your state), with no Spanish tax at all.
For many people, US rates on a planned partial liquidation — especially spread over two or three pre-move years — are meaningfully lower than Spanish general-base rates of up to 47%.
Careful: Roth conversions done shortly before the move only make sense if you then follow priority one and understand that post-move Roth growth is Spanish-taxable anyway. Converting to Roth and then moving to Spain without a distribution plan can combine the worst of both worlds.
Spanish tax residency is generally triggered by spending more than 183 days in Spain in a calendar year (among other tests), and Spain does not split the tax year: you are resident or non-resident for the entire year. A move in, say, September 2026 usually means you are still a US-only taxpayer for all of 2026 — a final planning window many people waste.
Does the Beckham regime protect your retirement accounts?
The special expat regime of article 93 LIRPF — the "Beckham Law" — is a genuine opportunity for those who qualify (broadly: relocating to Spain to work as an employee, as a qualifying director, or under the digital-nomad entrepreneur routes, without Spanish residence in the previous five years).
Under Beckham, for up to six tax years you are taxed as a quasi-non-resident: foreign-source investment income and, on the prevailing interpretation, foreign pension distributions fall outside the Spanish net. In practice this can create a window in which 401(k)/IRA distributions and Roth growth escape Spanish taxation.
Three caveats:
Beckham is for people moving to work. A pure retiree on a non-lucrative visa does not qualify.
The window closes. Year seven, you are a fully ordinary Spanish taxpayer, RMDs and all. Beckham is a deferral corridor, not a permanent shield — use those six years to restructure.
Beckham taxpayers file Form 151, not the ordinary IRPF return, and are generally outside Modelo 720 — one of the regime's quiet advantages.
What about US withholding, RMDs and the foreign tax credit?
Once you are a Spanish resident, the mechanics of a distribution typically look like this:
Your US custodian may apply US withholding on the distribution. As a US citizen you remain subject to US tax on worldwide income regardless of the treaty (the "saving clause"), so you will also file a US return.
Spain, as your residence country, taxes the distribution under its own rules as described above.
Double taxation is corrected through the foreign tax credit of article 80 LIRPF (and, on the US side, through the treaty's re-sourcing mechanics for US citizens). Broadly, Spain credits the US tax actually and properly paid on the same income, capped at the Spanish tax attributable to it. Since Spanish rates on pension income are usually higher than the effective US rate, you generally end up paying the Spanish level overall — Spain simply keeps the difference.
RMDs deserve emphasis: from age 73/75 the IRS forces annual distributions whether you want them or not, and Spain taxes each one in the general base. If you arrive in Spain at 70 with a $2 million Traditional IRA, your future Spanish tax base is largely written already.
The interaction between the treaty's pension article, the saving clause and the credit is one of the most misunderstood corners of this field — I unpack it in the US–Spain tax treaty explained: pensions, Social Security, dividends and the saving clause. And note that US Social Security follows a different treaty rule than private retirement accounts — see how US Social Security benefits are taxed in Spain.
Do you have to report all three accounts on Modelo 720?
Modelo 720 is Spain's informational return on foreign assets over €50,000 per category. For US retirement accounts, the position as of 2026 is nuanced:
401(k) and Traditional IRA in accumulation phase: the general administrative doctrine is that consolidated pension rights not yet in payment are not reportable. Once the account is in payment phase (or vested rights become available, and certainly once you annuitise or draw), reporting obligations can be triggered.
Roth IRA: the harder case. Because you can withdraw at any time without restriction, a Roth looks less like a "pension right" and more like an ordinary investment account holding securities — and many practitioners report the underlying holdings prudently.
Once distributions start, any account fitting the reporting categories should be evaluated each year, and the proceeds landing in US brokerage or bank accounts are clearly within Modelo 720's scope.
Penalties are no longer the confiscatory pre-2022 regime after the EU Court of Justice ruling, but they are still real, and the prudent path — given the unsettled doctrine — is a considered, documented reporting position rather than silence.
So which account is taxed worst in Spain? The ranking
From worst to best, for a standard Spanish tax resident as of 2026:
Worst: Roth IRA. Not because its Spanish rate is the highest — 19%–30% is lower than the general base — but because the move to Spain creates tax where there was none. All accumulated growth loses its exemption, there is no US tax to credit, and the murky Spanish characterisation adds compliance risk. Biggest value destruction per euro.
Middle: Traditional IRA. Pension treatment at up to 47%, RMDs removing your timing control, and rollover grey areas. Slightly worse than the 401(k) in practice only because people tend to hold IRAs longer into RMD age; substantively they are near-identical.
Least bad: 401(k). Same pension treatment, but with the clearest treaty and administrative track record, the option to roll over or restructure before the move, and — critically — tax that was always going to be paid somewhere. Spain changes the rate, not the existence, of the tax.
One honest nuance: if you compare pure rates, the Roth's 19%–30% savings-base treatment beats the 401(k)'s up-to-47%. The ranking above is about damage caused by the move — how much worse each account fares in Spain than it would have fared had you stayed. On that measure, the Roth loses the most, precisely because it had the most to lose.
Three real-world scenarios
Scenario 1: Mark, 55, moving to Valencia with a large 401(k)
Mark has $1.4 million in his 401(k) and wants to retire in Valencia in 2027. If he moves first and draws later, every dollar comes out as Spanish general-base income; a $90,000 annual drawdown faces a meaningful Spanish average rate, and any future lump sum (say, for a house) would be brutal at up to 47%. Instead, in 2026 — his last non-resident year — he takes a planned $250,000 distribution, paying only US tax at a controlled bracket, and earmarks it for the Spanish house purchase. He rolls the 401(k) into an IRA before moving to clean up the rollover question, then draws roughly $70,000 a year from Spain, crediting US tax under article 80. Result: the same money, materially lower lifetime tax, no grey areas.
Scenario 2: Priya, 34, digital nomad with a Roth IRA
Priya has $180,000 in a Roth ($95,000 of contributions, $85,000 of growth) and is eyeing Spain's digital-nomad visa. If she qualifies for the Beckham regime, her Roth growth stays outside the Spanish net for up to six years — but she should plan for year seven now, not in year six. If she will be an ordinary resident instead, the smart pre-move steps are: withdraw her $95,000 of contributions tax- and penalty-free before becoming resident (reinvesting in a taxable account with a fresh, stepped-up Spanish cost basis), and keep meticulous records of the remaining basis. Doing nothing means Spain eventually taxes all future growth at 19%–30% while the IRS taxes none of it — the credit mechanism gives her nothing back.
Scenario 3: Eleanor and Tom, 68, retiring to Málaga with a mix
Eleanor and Tom hold $900,000 in Traditional IRAs, $300,000 in Roths, plus US Social Security. They are five years from RMDs. Their pre-move year is spent doing triage: fully distributing the Roths (both are over 59½ and past five years — 100% tax-free in the US, and forever outside Spain's reach), and running partial IRA distributions up to the top of a moderate US bracket to shrink the future RMD base. After the move, their Spanish return combines IRA drawdowns as pension income with article 80 credits, Social Security under its own treaty article, and a clean Modelo 720 file for their remaining US brokerage and bank accounts. Same wealth, but the sequencing saves them well into six figures over their retirement.
Pre-move checklist: the year before you become a Spanish tax resident
Pin down your residency start date. Count your 183 days; remember Spain has no split year. Your last full non-resident calendar year is your planning window.
Qualified Roth? Distribute before the move. If you are 59½+ and past the five-year rule, take it out tax-free while only the US rules apply.
Under 59½ with a Roth? Withdraw contributions and document remaining basis to the dollar (statements, Form 5498 history, contribution records).
Model pre-move 401(k)/IRA distributions or conversions. Compare your US bracket on a planned liquidation against Spain's up-to-47% general base on future drawdowns.
Do rollovers before, not after. Consolidate 401(k)s into an IRA while non-resident to avoid Spanish characterisation questions.
Check your Beckham eligibility if you will work from Spain — and if you qualify, build a six-year restructuring plan, not just a six-year holiday.
Project your RMDs. If forced distributions will start within a decade, every dollar you shift out pre-move is a dollar Spain never taxes at 47%.
Leave your high-tax state properly before taking large distributions — state tax has no Spanish credit angle and is pure cost.
Prepare your Modelo 720 position for year one: inventory accounts, values and characterisation before the March filing window arrives.
Get advice on both sides. The expensive mistakes in this field are almost always made by advisers who see only one of the two systems.
Conclusion: the Roth loses the most — but only if you let it
Spain does not treat US retirement accounts cruelly; it treats them indifferently, forcing them into Spanish categories that were never designed for them. The 401(k) and Traditional IRA translate tolerably — pension income, high rates, but predictable and creditable. The Roth IRA translates terribly, because its entire value proposition — tax-free growth — simply does not exist in Spanish law as of 2026.
The good news is that almost all of the damage is avoidable with sequencing: what you distribute, convert and document in the year before the move determines your Spanish tax life for decades. The bad news is that the window closes silently, on a residency test most people trip without noticing.
If you are planning a move to Spain with US retirement accounts, I review your specific mix — accounts, ages, visa route and timeline — and give you a concrete pre-move action plan.
WhatsApp: +34 644 12 18 02
Book a video call: Calendly — consultation with Jacob Salama
Email: taxlegalspain@gmail.com
Disclaimer: This article is general information as of 2026, not legal or tax advice for your specific situation. Spanish administrative doctrine on US retirement accounts is evolving, and the right strategy depends on your residency timeline, account composition and personal circumstances. Always seek individual advice before acting.