How is my US 401(k) or IRA taxed once I move back to Ireland?
Short answer: Under the US–Ireland tax treaty, periodic pension payments from a US 401(k) or IRA to an Irish resident are generally taxable in Ireland as income, subject to income tax and USC. Growth inside the plan is generally not taxed annually. Lump sums and Roth accounts need specific review because Irish treatment does not automatically mirror US treatment.
Written and reviewed by Anthony Walsh, Selanis. Last reviewed 2026-10-06.
Why it works this way
The treaty generally allocates the taxing right on private pensions to the country of residence. Filing a W-8BEN with the plan reduces US withholding so you are not paying twice.
Irish tax on pension income includes income tax at 20% or 40% and USC. Withdrawals can be planned across tax years to use lower bands.
Roth distributions are tax-free in the US but have no direct Irish equivalent. Whether Ireland taxes the growth element depends on the facts, so take advice before large withdrawals.
The expensive mistake: Transferring the 401(k) into an Irish pension
There is generally no tax-free route from a 401(k) into an Irish PRSA. Attempting it usually means a taxable US distribution plus penalties.
What to do
- Keep the plan where it is — Check the administrator accepts an Irish address, and file a W-8BEN.
- Map withdrawals to Irish bands — Plan the amount drawn each year against the 20% band and USC thresholds.
- Review any Roth — Get an Irish tax view before drawing on Roth balances.