Expat Retirement Planning: The Technical Reality You Need to Know

Retirement planning stops being simple the moment you add a second country.

You don't just need to know how much you'll spend. You need to know where you'll owe tax. What your pensions are actually worth after the treaty kicks in. Whether you're triggering a 25% penalty on your entire pension fund. Whether your state pension even exists once you leave.

This isn't lifestyle planning. This is the part that breaks most expat retirements.

The short version: most expats pay more tax than they need to because they plan the move and figure out the tax afterwards. If you're a US citizen, the Foreign Tax Credit is your main tool — it offsets foreign taxes against your US federal bill, but it doesn't cover everything. If you're a UK national, the 2027 inheritance tax change to pension funds is the thing most financial advisers still haven't fully absorbed. For both: the double-tax treaty between your home country and your destination determines who taxes what, and it's almost never what you'd guess.

The Three Mistakes Most Expats Make

Mistake 1: Moving first, planning tax later.

You move to Spain. You start drawing your UK pension. Six months in, your accountant tells you that pension income is taxed at 24% in Spain, not the 20% you expected. You've just lost €4,000 of your first year's income. Should have known the Spain double-tax treaty gives Spain taxing rights, not the UK.

Mistake 2: Assuming pensions are portable.

They're not. UK SIPP rules let you draw flexibly in the UK. Move to Spain and that same SIPP? Now subject to Spanish withholding rules. Different provider, different rules.

Mistake 3: Not knowing what April 2027 does to your pension.

From April 2027, unused UK pension funds are being counted in your estate for inheritance tax. If you have £500k in a SIPP and you die, that £500k is now subject to 40% IHT. It wasn't before. Planning before that date is not optional if you have significant pension savings.

For US Citizens: The Foreign Tax Credit and the Permanent Filing Requirement

The trap: You still owe US federal tax on worldwide income. That includes:

• Social Security benefits (up to 85% taxable depending on provisional income)
• 401(k) distributions
• IRA withdrawals
• Foreign pension income

You move to Portugal and think you're done with the IRS. You're not.

How it actually works:
Most US tax treaties give your country of residence the right to tax your pension income. You pay tax in Portugal. You claim a Foreign Tax Credit on your US return for taxes paid to Portugal. If Portugal's tax is higher than US tax, the FTC stops double taxation. If Portugal's is lower, you owe the difference to the US.

Example: You draw $50,000 from a traditional IRA in Portugal. Portugal taxes it at 15% = $7,500. The US would tax it at ~20% = $10,000. FTC covers $7,500, you owe $2,500 to the US.

It works. But you have to file US taxes every year, from Portugal, for life.

For UK Expats: The Pension Transfer Trap

Here's what changed: If you move abroad and transfer your UK pension to an overseas scheme (QROPS), you now pay 25% tax on the transfer value. There used to be exemptions. They're gone.

What most advisers say: Don't transfer. Keep your SIPP in the UK.

Why that might be right: Keeping your UK SIPP while resident abroad is actually more flexible now. You draw what you need each year. You can manage withdrawals to stay within Spanish tax bands. If you need €20,000 one year and €30,000 the next, you can control that.

Why you might still transfer: Currency stability. If you're drawing euros and your UK pension is in pounds, you're exposed to GBP/EUR movements. A strong pound benefits you. A weak pound kills your buying power. Some people accept the 25% hit to get into euros permanently.

For UK Expats Retiring to Spain or Portugal: Where Tax Actually Goes

For a practical comparison of costs, visa requirements, and healthcare in both countries, see the best expat retirement countries in 2026. If Portugal is on your shortlist, the full Portugal retirement guide has the 2026 tax brackets and worked examples for US and UK pension income. Here's the tax layer on top of that.

Spain (Non-Lucrative Visa)

• UK State Pension: Taxable in Spain only (treaty). Paid gross by the UK. You declare on your Spanish return.
• SIPP/workplace pension: Taxable in Spain as ordinary income. The UK-Spain treaty gives Spain taxing rights.
• Tax rates: 24% on the first €18,000, rising to 45% above that.
• Good news: You can take your pension lump sum tax-free in the UK, move to Spain, and draw the balance slowly to manage tax bands.

Portugal

• UK State Pension: Paid in UK currency to your UK account or converted to euros for a Portuguese account — your choice.
• UK pension income: Progressive rates from 12.5% on first €8,342 up to 48% above €86,634.
• Lump sums are painful. Taking £100k as a lump sum in your first year in Portugal could push you into the 45%+ bracket. Taking it over three years spreads the tax burden.

Double tax treaty reality:
The treaty works. Spain doesn't tax you twice. Neither does Portugal. But the treaty gives your country of residence the primary taxing right, not the UK. So you pay Spanish or Portuguese tax first. Then claim anything already paid as a credit in the UK. Usually, the credit covers everything.

Multi-Currency: The €3,000/Year Problem Most Expats Ignore

You have a UK pension in pounds. You live in Spain and need euros. Every month, you convert. GBP/EUR matters enormously over 25+ years.

Example: £20,000/year pension. GBP/EUR at 1.20 = €24,000/year. GBP/EUR at 1.05 = €21,000/year. That's a €3,000/year swing — just from currency. Over a decade, that's €30,000 of lost income on a single exchange rate move.

Three options, simplest first:

• Regular payment plans: Convert monthly at specialist rates (slightly better than bank rates). No forward contract — you get whatever rate happens. Administratively simple.
• Forward contracts: Lock the rate for future transfers (e.g., 12 months out). Trade timing risk for certainty. If the pound strengthens, you miss it. If it weakens, you're protected.
• International SIPP: Hold euros directly in your pension. No currency conversion needed. Slower to set up, solves the problem long-term.

Most expats run a payment plan without thinking about it. A forward contract would cost them minutes to set up and could save them thousands.

What to Sort Out Before You Move

Before you move:

1. Know your country's tax treaties. Download them from the IRS or HMRC. The treaty article on pensions is what matters.
2. Run the tax math. Not estimates — actual tax on your specific pension income in the country you're considering. This often requires professional help.
3. Check pension portability. US 401(k) to anywhere = can't transfer, only distribute and reinvest. UK SIPP to Spain = likely a £50k+ hit. Check the restrictions and costs for your specific accounts.
4. Understand your state pension and when it applies. UK State Pension works in most countries. But some freeze it — Australia, Canada, South Africa. Retiring there has a long-term cost.
5. Model multi-currency scenarios. What's your pound-to-local-currency assumption? If it strengthens 15%, how does that change your lifestyle? If it weakens 15%, are you still okay?
6. Get specialist advice. Not a general accountant. Someone who does expat retirement planning in your specific country pair. UK-Spain is different from Australia-US is different from Canada-Mexico.

The Calculation You Need to Run

Before you commit to a country, you need to answer this question: after tax in my chosen country, plus currency conversion, what is my actual monthly income?

Not hoped-for. Actual. Here's how it looks for a US/UK expat retiring to Spain:

Your actual monthly spending power: €2,217 + $2,083 converted at your own rate. That's the real number. Not the gross. The net, converted.

Anywhere you see estimates that don't include the tax and currency layer, they're underestimates.

Final Word

The order matters: run the tax math before you pick the country, not after you've signed a lease. Get advice specific to your country pair — UK-Spain is different from UK-Portugal, which is different from US-Spain. Run the actual numbers with your actual pension amounts, not approximations. Then stress-test it: what if the pound drops 15%? What if healthcare costs twice what you estimated?

Most people skip the stress-test. That's the step that separates a retirement plan from a retirement hope.