By Dako
If you have family in Japan, you’ve heard some version of it. “Put that into a NISA. It’s tax-free now, forever.” The US side says 529, usually with less explanation. Both sides are describing a real thing. Neither side knows that our kids might grow up half in each country, and that the two accounts stop being comparable the moment a family crosses the ocean.
We don’t know where our kids will go to school yet. We don’t know which country we’ll live in when they’re old enough for it to matter. What we do know is that the money has to start growing now, and that “wait until we decide” is its own decision. Under it sits the real worry: does 529 money go to waste if we end up in Japan? So this post is about choosing a container for a future you haven’t picked, and about what happens to each container when it gets shipped abroad.
The problem is the future, not the accounts
A 529 plan is a US account built for education, with a US tax benefit and US strings attached. A NISA is a Japanese account built for anything, with a Japanese tax benefit and Japanese residency attached. Each one is excellent inside its own border. The trouble starts when the parent, the child, or the school is on the wrong side of that border, and a family that hasn’t decided where it’s going can’t rule any of those out.
The useful question isn’t “which one is better.” It’s “which one survives being wrong.” If we fund a 529 and end up in Japan, what breaks? If we open a NISA and stay in the US, what breaks? Those turned out to have very different answers.
How a 529 works, and what happens when you leave
Money goes in after tax. It grows untaxed. Come out for qualified education costs and the growth is never taxed at all. The list of qualified costs got longer in 2025 and 2026. College tuition, fees, books, room and board. Up to $20,000 a year for K-12 tuition, and now K-12 items like curriculum materials, tutoring, and standardized test fees. Registered apprenticeships count. So do fees for certain professional credentials.
Use the money for something else and only the growth is hit: ordinary income tax on the earnings plus a 10% additional tax. Your contributions come back untaxed no matter what. There are exceptions to the 10% too, for a scholarship, a death, a disability, or a military academy appointment. And once the account is 15 years old, up to $35,000 can move into the beneficiary’s Roth IRA over time. The yearly IRA limits still apply, and the last five years of contributions can’t move. You can also switch the beneficiary to another family member without tax.
That’s the part that made me relax about a 529. Worst case, a kid who never uses it for school gets a Roth seed and a taxable withdrawal of the rest, minus 10% of the gains. That’s not a disaster. That’s a mildly annoying brokerage account.
Now the border. A 529 doesn’t close when the owner moves. It’s a US account, and a household like ours would keep filing US returns after a move, so the federal treatment would travel too. What doesn’t travel cleanly is the address. The plans I read require a US street address and a Social Security number to open an account. None of the plan documents I found said what happens to an existing account once the owner’s only address is in Japan. That’s a phone call to the plan before any move, not after.
The bigger unknown is the Japanese side. Japan doesn’t recognize a 529 as anything special. I couldn’t find a single primary source on how a Japan-resident owner is taxed on the growth or the withdrawals, only practitioners saying no treaty protects the wrapper. And there’s a gift tax angle too. Japan exempts education and living costs paid by a parent, but only money spent “as needed” for the purpose. Money set aside as savings or investments doesn’t qualify under that rule. Whether a 529 withdrawal to pay a Japanese school fits the exemption is exactly the kind of question I’d want answered in writing.
One more thing, because it’s the question a Japanese family will ask first: can a 529 pay for a university in Japan? Only if the school participates in US federal student aid. A handful of Japanese universities appear on a federal list I found, but the list has no date and some entries cover a single program. That’s a whole post of its own, coming in the spring. For now, treat it as “possibly, verify,” not “yes.”
How NISA works, and the trap for US-person parents
NISA is Japan’s tax-free investment account, and since 2024 it’s a generous one. Up to ¥1.2 million a year in the accumulation slot and ¥2.4 million in the growth slot, under a lifetime cap of ¥18 million. The exemption never expires, and the cap refills the year after you sell. No education requirement. You can spend it on tuition or a kitchen renovation, and Japan won’t ask.
Kids haven’t been able to hold one since 2024. Junior NISA closed to new money at the end of 2023, and the adult account requires being 18 on January 1. That changes in 2027. A law passed this March creates a children’s NISA starting January 1, 2027. It allows ¥600,000 a year under a ¥6 million lifetime cap, withdrawals from age 12 with the child’s consent, and limited uses for the money before 18. If we were living in Japan, that’s the account I’d be reading about right now.
We’re not, and that’s where it falls apart. Two conditions run through every version of NISA: you have to be a resident of Japan, and the account has to be at a Japanese brokerage. The first rules out any US-based family today. The second creates the problem for a family that moves later. Leave Japan for anything other than a temporary work transfer, and the NISA account is closed and its holdings dumped into a taxable account. Even the transfer exception caps out at five years, freezes new purchases, and only works at brokerages that offer it.
And for a US citizen or green card holder, the account is worse than useless. The IRS doesn’t recognize the NISA wrapper, so every gain is taxable in the US. The funds inside are Japanese-domiciled, which makes them PFICs, with a Form 8621 for each one and a tax treatment designed to punish. Our portfolio has no NISA for exactly that reason. A child’s account doesn’t escape it if the child is a US person too.
So when someone in Japan says “just open a NISA,” they aren’t wrong about NISA. They’re picturing a family that lives in Japan, pays tax in Japan, and stays. Not ours, at least for now.
The decision, by scenario
Laid out as a matrix, this comes out lopsided, and I left it that way.
If we stay in the US, the 529 wins without a contest. NISA was never on the table.
If we do a full move to Japan, the 529 becomes a US account we own from abroad. It’s still tax-free on the US return, its Japanese treatment is unsettled, and its usefulness depends on where the kids study. The Japanese universities question decides a lot. From 2027 the children’s NISA opens up once we’re residents, so that’s the moment to open one, not before. The 529 doesn’t get emptied. It gets paused, and possibly pointed at a US degree or a Roth.
If we split time between countries, the tax residency of the parent who owns the account decides more than the account does. That’s the dual-residency problem again, wearing a school uniform. I don’t know how a 529 owned by someone Japan considers a resident gets taxed, and nobody I read does either with confidence.
What the lopsided matrix says is simple. A NISA fails in every column where we stay in the US. A 529 only gets awkward in the columns where we leave, and even there it keeps its exits. So the container we picked is the one that’s wrong in the smallest way in every column.
What we’re doing for our own kids
We fund a 529. It’s a direct-sold plan invested in low-cost index funds, and we make one contribution at the start of each year, up to the amount our state gives a tax deduction for. That deduction is the only reason the timing matters. Beyond it, the account is just a place where money compounds in dollars.
The Coverdell is out of our hands. Its income cap, unadjusted since it was written, rules us out, so the grandparents fund that one. We also went through the Trump account signup, which works differently: government-seeded, indexed, and locked for years. Not education savings.
We hold no NISA, and won’t while we live here. If we move, the order is fixed. Confirm what the 529 plan does with a Japanese address. Ask a Japanese tax professional how the account is treated. Then open a children’s NISA once the residency requirement is met, and not before.
The kids are still little, and we haven’t started the money conversation with them. When we do, I’d like the account behind it to be one that doesn’t need a country picked first. For now, that’s the 529, with its exits mapped.
FAQ
If we move to Japan, should we cash out the 529 before leaving?
I wouldn’t. Cashing out triggers tax and a 10% penalty on all the growth at once, while keeping it adds no US tax and leaves a US degree or a Roth rollover open. Get the Japanese treatment confirmed by a professional first. Then decide.
Can our kids open a NISA once they’re adults in Japan?
Yes, if they’re Japanese residents on January 1 of the year and 18 or older. US persons carry the PFIC rules in with them. That’s a conversation for when they’re grown, and it turns on their citizenship rather than ours.
Is the 2027 children’s NISA an option for a family in the US?
No. Like every other NISA, it requires the child to be a Japanese resident. After a move, yes. Before, no.
Can grandparents in Japan help with education costs without tax trouble?
Japan’s exemption for education money from a family member applies to costs paid as they come up, not to lump sums saved or invested. The separate ¥15 million lump-sum education gift program ended on March 31, 2026. Anything larger than paying a bill directly deserves a professional’s eyes on both sides.
This article is general information about US and Japanese education savings rules, not legal, tax, or investment advice. Figures are 2026 amounts and change yearly, and the 2027 children’s NISA is based on the law as passed, not on brokerage rules that don’t exist yet. Cross-border treatment of a 529 is unsettled, and I’ve flagged where I couldn’t find official guidance. Please work with qualified professionals in both countries before acting, and see our Disclaimer for details.