The short answer
If you're a foreign resident working in Japan, the question of whether you need to file 確定申告 (kakutei shinkoku, "final tax return") is one of the most common sources of confusion each tax season. The honest answer is: it depends on your situation, but for a large share of salaried employees, the answer is that you likely don't need to file anything at all.
This guide walks through the logic step by step, the same way our filing checker does, so you can see where you likely land before you commit to hours of paperwork — or before you miss a filing that would have gotten you a refund.
The baseline: most employees don't need to file
If you have exactly one employer in Japan, and that employer withholds income tax from your salary throughout the year, they perform something called 年末調整 (nenmatsu chosei, "year-end adjustment") in December. This process reconciles your withheld tax against what you actually owed, applies your standard deductions, and settles your account. If that's your whole situation — one employer, no other income — you likely don't need to file a 確定申告 at all. The system has already done the work for you. For a deeper look at how this compares to a full tax return, see our breakdown of 年末調整 vs 確定申告.
When you likely must file
Several situations override the baseline and mean you likely do need to file. None of these are exotic — many ordinary residents hit at least one of them without realizing it.
| Situation | Why it triggers filing |
|---|---|
| Gross salary over ¥20,000,000 (2,000万円) | Your employer is not permitted to perform 年末調整 above this threshold, so you must settle your own tax. |
| One employer, but over ¥200,000 in other income | The 20万円 rule — side income (freelance work, investments, etc.) above this amount on top of a 年末調整'd salary requires filing. |
| Two or more employers | Only your main job typically gets 年末調整; income from the other job(s), combined with any other income, is measured against the same ¥200,000 threshold. |
| Freelance or business income | You file if your income exceeds your deductions and tax is actually due — this is a tax-due test, not a fixed revenue line. |
| Crypto or stock gains outside a 特定口座（源泉徴収あり） | Without a withholding-enabled specified account, gains aren't automatically taxed at the source. |
| Leaving Japan mid-year | You generally need to file before departure or appoint a 納税管理人 (tax administrator) to file on your behalf. |
If your situation involves side income specifically, our detailed explainer on the ¥200,000 side-income rule walks through common edge cases — things like occasional freelance invoices, affiliate income, or a second part-time job. And if you run your own business or work as a freelancer, our first-year freelancer tax guide covers what "income exceeds deductions" actually means in practice, since there's no single revenue number that triggers filing on its own.
If you're relocating out of Japan partway through the year, timing matters — see leaving Japan and your taxes for what to file and when, including how a 納税管理人 works if you can't file before you go.
When filing is optional but worth it
Some situations don't require you to file — but filing anyway can put money back in your pocket. These are worth checking even if the mandatory triggers above don't apply to you.
- Medical expenses (医療費控除): if your household's out-of-pocket medical costs were significant during the year, filing can generate a refund.
- First-year housing loan credit (住宅ローン控除): the first year you claim this mortgage tax credit, you must file a 確定申告 even if you're an ordinary employee; later years can usually be handled through your employer.
- ふるさと納税 beyond the one-stop system, or across 6+ municipalities: the one-stop exemption only covers up to five donation destinations per year and doesn't apply if you're already required to file for another reason. Our ふるさと納税 and tax filing guide explains when the one-stop form is enough and when it isn't.
- Left a job mid-year without a replacement 年末調整: if you stopped working partway through the year and no subsequent employer performed a year-end adjustment on your behalf, you likely overpaid tax and can file a 還付申告 (refund return) — and you have up to five years to do so.
The resident tax catch
Even if the ¥200,000 rule means you're exempt from national 確定申告, that exemption applies to income tax only. 住民税 (resident tax) has no equivalent threshold, so you generally still owe a municipal 住民税申告 (resident tax declaration) covering that same side income. Filing a full 確定申告 automatically covers both taxes at once, which is often the simpler path even when it isn't strictly required.
When to see a professional
Some situations sit outside what general guidance can safely cover: non-resident (非居住者) status splits partway through the year, tax-treaty positions between Japan and your home country, and foreign-asset reporting obligations. If any of these apply to you, it's worth a consultation with a 税理士 (licensed tax accountant) or a visit to your local 税務署 (tax office) rather than relying on general rules of thumb.
For English-language resources to help you prepare — including where to find English tax office support and e-Tax guidance — see our tax filing English resources page, or browse our FAQ for quick answers to common questions.
This article is general information, not tax advice. Every situation has edge cases — when in doubt, confirm with a 税理士 or your local 税務署.