Many US employers offer a retirement savings plan. Even if you are not sure you will stay, it is often worth joining, especially for the match.
A 401(k) is a retirement account through your job (403(b) at schools and nonprofits).
Money comes straight from your paycheck.
Traditional: you pay less income tax now; you pay tax when you take the money out.
Roth: you pay tax now; qualified withdrawals later are tax-free.
2026 limit for your own contributions: $24,500 (more if you are 50 or older).
Many employers add money if you contribute. Example: "100% match up to 4% of pay." You earn $60,000 and put in 4% ($2,400). Your employer adds $2,400. That is free money.
Check the vesting schedule: the employer's money may become fully yours only after you work there for a certain time. Your own contributions are always yours.
Find the 401(k) link in your benefits portal, usually in your first 30 to 60 days.
Choose a percentage, at least enough to get the full match.
Choose investments. Many people pick a target date fund (a fund for the year you expect to retire).
Name a beneficiary (who gets the money if you die).
An IRA (individual retirement account) is opened by you at a bank or brokerage, not through work. 2026 limit: $7,500 (more at 50 or older). You need earned income (pay from work) to contribute. Roth IRA eligibility depends on income.
Your 401(k) or IRA stays yours. You can leave it invested in the US.
If you take money out before age 59 and a half, you usually pay income tax plus a 10% extra tax, with some exceptions.
Nonresidents often have tax withheld from withdrawals, usually 30% unless a treaty gives a lower rate.
Your home country may tax it too. Check before you cash out.
Keep your US login, a US mailing address or updated foreign address, and the plan's phone number.
Social Security when you leave
Social Security tax you paid is not refunded when you leave. To get a US retirement pension, you usually need 40 credits (about 10 years of work). The US has totalization agreements with some countries that can combine work years and stop double social tax. Check the list on ssa.gov.
Not joining and losing the match.
Cashing out the 401(k) when changing jobs. You can usually roll it over to your new plan or an IRA with no tax.
Leaving an old account and forgetting it. Keep a list of every account.