If you're not a US citizen and you might leave the country someday, a 401(k) is still worth your money. The reason is simple: the employer match is free money. If your company adds 50 cents for every dollar you put in, that's an instant 50% return. No tax strategy beats that. Take the match first, always.
The harder question is what comes after the match. Should you use a traditional (pre-tax) 401(k), a Roth 401(k), a Roth IRA, or just a regular taxable brokerage account? For a US citizen, there are clean answers. For someone who might retire abroad, the default rules stop applying. Once you leave and become a non-resident alien, the way the US taxes your withdrawals changes completely.
This guide walks through what actually happens to a 401(k) when you leave the US, why the popular "just do Roth" advice can backfire for expats, and how to think about the decision. One warning up front: this is genuinely complex, it depends heavily on which country you end up in, and the rules change. Treat this as a map, not a final answer.
First, the easy part: take the employer match
Whatever else you do, contribute enough to capture your full employer match. This is true whether you stay or leave. The match goes into your account regardless of your citizenship or where you retire.
Say you earn $90,000 and your employer matches 100% of the first 5%. That's $4,500 of your money and $4,500 of theirs every year. Walking away from that is like turning down a raise. Even if you later pay 30% US withholding on the withdrawal, you're paying 30% on money that doubled the moment it went in. The math still wins easily.
For 2026, you can defer up to $24,500 of your own salary into a 401(k). But you don't need to max it out to get the full match. Find your match threshold, hit that, then decide what to do with the rest.
What happens to your 401(k) when you leave the US
Here's the part most people don't know. When you leave the US permanently, you generally become a non-resident alien, or NRA. An NRA is someone who is neither a US citizen nor a green-card holder and who doesn't meet the test for being a US tax resident.
When an NRA takes money out of a US retirement account, the US doesn't tax it the way it taxes a resident. Instead, the plan administrator withholds a flat 30% before sending you the rest. This isn't your marginal income tax rate. It's a fixed withholding rate that applies to NRAs regardless of how much you withdraw.
So the comfortable assumption that you'll withdraw in retirement at a low bracket may not hold. A US resident retiree might pay an effective rate well under 15% on modest withdrawals. An NRA could face a flat 30% on the same dollars unless a tax treaty lowers it. That single fact reshapes the whole traditional-vs-Roth comparison.
Your money also doesn't disappear or get frozen, despite a common fear. You can usually still access a 401(k) as an NRA. Some US brokerages restrict accounts for non-residents, which can mean limited trading or being asked to move the account, so that's worth checking with your provider. But the account itself remains yours.
The treaty variable
The 30% withholding is the default, not the destination. The US has tax treaties with many countries, and a lot of those treaties reduce the rate on pensions and retirement distributions. The catch is that the rate depends entirely on the specific treaty with the specific country you move to.
A few rough examples, all of which you must verify before relying on them:
| Country | Typical US withholding on pensions | Who taxes the remainder |
|---|---|---|
| Canada | ~15% (cap on periodic pension payments) | Canada, typically with a credit for the US tax |
| United Kingdom | Often 0% | The UK taxes instead |
| Germany | ~15% | Germany taxes the withdrawal |
| No US treaty | 30% (full default rate) | Your home country may also tax it |
I'm flagging these as approximate on purpose. Treaty rates differ for lump-sum withdrawals versus periodic pension payments, they have technical conditions, and they get renegotiated. Two people retiring in two different countries can face completely different outcomes on the identical account. So "what's the withholding where I'm going?" is a question you answer per country, not in general.
Why Roth can be worse for expats
Inside the US, the Roth pitch is clean: pay tax now, withdraw tax-free later. For someone planning to retire abroad, that logic can quietly fall apart.
The problem is that "tax-free" is a US promise. Many foreign countries don't recognize a US Roth account as tax-exempt. They see a retirement withdrawal and tax it under their own rules. So you'd pay US tax on the contributions today, then pay foreign tax on the same money when you withdraw it. That's the double-tax trap, and it's the opposite of what Roth is supposed to do.
Compare that to a traditional pre-tax 401(k). You skip US tax today at your current 24% bracket (2026). Later, as an NRA, you face US withholding at the treaty rate, and your new home country taxes the withdrawal under its rules. Crucially, many countries give you a foreign tax credit for the US tax you already paid, so you're not taxed twice on the same dollars. The two systems coordinate. With a Roth, that coordination often doesn't exist, because the foreign country never agreed the money was tax-free.
A simplified example. Suppose you're in the 24% US bracket now (2026) and you eventually retire in a country with a 15% treaty withholding rate that grants a foreign tax credit.
| Traditional route | Roth route | |
|---|---|---|
| Tax now | None — the deduction saves you 24% up front | Full 24%, paid up front |
| Tax at withdrawal (US) | 15% treaty withholding | 0% — Roth is US-tax-free |
| Foreign tax + credit | Home country taxes the withdrawal but credits the US tax you paid | Home country may tax it again, with no US tax to credit |
| Net outcome | Combined drag may land below your original 24% | Potential double tax: 24% now plus foreign tax later |
In that scenario, traditional wins, sometimes by a wide margin. This is the reverse of the usual young-person advice, and it's driven entirely by the expat angle.
The brokerage account angle
Don't overlook a plain taxable brokerage account. For someone with an uncertain future country, flexibility has real value, and brokerage accounts are often the most flexible option.
A few reasons it can fit expats well. There's no early-withdrawal penalty, so you can access the money at any age. Long-term capital gains, meaning gains on assets held more than a year, are taxed at lower rates than ordinary income. And for NRAs, US capital gains are frequently not subject to US tax at all, since the US generally doesn't tax an NRA's capital gains from US securities, though it does tax US dividends, often at 30% or a treaty rate.
The trade-off is that you contribute with after-tax dollars and you don't get tax-deferred growth like a 401(k). But you keep total control and avoid the retirement-account withholding maze. For money beyond the employer match, when you genuinely don't know where you'll land, a brokerage account is a reasonable home precisely because it travels well.
A framework for deciding
You can't optimize this without naming some assumptions. Work through these questions in order.
- Have you captured the full employer match? If not, do that before anything else. Nothing here changes that.
- What country do you realistically expect to retire in? If you truly have no idea, lean toward flexibility, which favors traditional plus a brokerage account over Roth.
- Does that country have a US tax treaty, and what's the pension withholding rate? A low treaty rate strengthens the case for pre-tax traditional contributions.
- Does that country recognize a US Roth as tax-exempt? If you can't confirm it does, be cautious about loading up on Roth. The double-tax risk is real.
- How likely are you to stay in the US after all? The more likely you stay, the more the standard US Roth-vs-traditional analysis applies, and Roth looks better for a young person in the 24% bracket (2026).
Notice that uncertainty itself points somewhere. When you can't answer questions 2 through 4, the safer defaults are the match, then pre-tax traditional, then a taxable brokerage account, with Roth used carefully rather than as the automatic choice.
Where this leaves you
The honest summary is that your situation sits at the intersection of two tax systems, and the answer depends on a country you may not have chosen yet. The employer match is the one piece that's certain. After that, the right mix turns on treaty rates, foreign recognition of Roth accounts, and rules that genuinely change over time.
This is one of the cases where a CPA with real international tax experience earns their fee. Someone who knows the US-side rules and the treaty for your likely destination can run the actual numbers, including the foreign tax credit interaction, before you lock in years of contributions.
You can still pin down the US side of the decision today. Run your current contributions through the [Roth vs. Traditional analyzer](/calculators/roth-vs-traditional) to see what the choice costs or saves you under US rules at your 24% bracket (2026). That gives you the domestic baseline. Then take that baseline to an international tax professional who can layer your future country on top of it.