iDeCo vs NISA: Which Is Right for You?

What is iDeCo? — 個人型確定拠出年金

iDeCo (individual-type Defined Contribution pension) is Japan's private pension program, officially called 個人型確定拠出年金. It was established under the 確定拠出年金法 (Defined Contribution Pension Act) and is administered by the National Pension Fund Association (国民年金基金連合会).

Think of iDeCo as Japan's equivalent of a US 401(k) or UK SIPP. You make regular monthly contributions from your pre-tax income into an investment account, choose from a selection of funds, and the money grows tax-free until you withdraw it at retirement (age 60 or later). The key selling point: every yen you contribute is fully deductible from your taxable income, giving you an immediate tax saving of 20-30% depending on your income bracket.

iDeCo has been available since 2001, but the system was significantly expanded in 2017 to allow almost all working residents of Japan to participate — including company employees, civil servants, self-employed individuals, and homemakers. As of 2024, more than 3.2 million people in Japan have iDeCo accounts, and enrollment is growing rapidly.

The trade-off is simple: iDeCo gives you more tax benefits than NISA (tax deduction on contributions + tax-free growth + favorable withdrawal taxation), but your money is completely locked until age 60. You cannot withdraw early for any reason other than severe disability or death. This makes iDeCo a serious long-term commitment — and one that requires careful consideration for foreigners who may leave Japan.

NISA vs iDeCo: full comparison — 徹底比較

Both programs shelter your investments from tax, but they work very differently. Here's a detailed side-by-side comparison:

In plain terms: NISA is a savings account with a tax-free wrapper. iDeCo is a retirement lock-box with a tax deduction at the door. NISA prioritizes flexibility; iDeCo prioritizes maximum tax efficiency for people committed to staying in Japan through retirement.

iDeCo's triple tax benefit — 三つの税制優遇

iDeCo's greatest advantage over NISA is its triple-layer tax benefit. While NISA offers one tax benefit (tax-free gains), iDeCo offers three. Understanding each layer helps you calculate the real value of iDeCo for your situation.

For a typical company employee contributing ¥23,000/month (¥276,000/year) with a taxable income around ¥5M, the tax savings alone are roughly ¥55,200 per year — a guaranteed 20% return before your investments even do anything. Over 20 years, that's over ¥1.1M in tax savings from contributions alone.

• Lump sum (一時金) — taxed as 退職所得 with the 退職所得控除 (retirement income deduction). If you contributed for 20 years: ¥8M deduction. For 30 years: ¥15M deduction. Only 50% of the amount above the deduction is taxable.
• Annuity (年金) — taxed as 雑所得 with the 公的年金等控除 (public pension deduction). At age 60-64, you get a ¥600,000 annual deduction. At 65+, the deduction rises to ¥1,100,000.

For many people, especially those with smaller iDeCo balances, the withdrawal deductions are large enough to eliminate withdrawal taxation entirely. This means you get a full tax deduction going in, tax-free growth, and zero tax coming out — effectively triple-free.

Contribution limits by employment type — 掛金の上限

Unlike NISA, which has the same limit for everyone, iDeCo contribution limits vary dramatically based on your employment type and whether your employer already provides a company pension plan. This is one of the most confusing aspects of iDeCo for foreigners.

For most foreigners working as regular employees (正社員): check with your HR department whether your company offers 企業型DC (company-type defined contribution pension) or DB (defined benefit pension). If you're not sure, ask about 企業年金 — they'll know. Many international companies in Japan, especially large ones, have some form of company pension that reduces your iDeCo limit.

For freelancers and self-employed (個人事業主 / 業務委託): you get the highest limit at ¥68,000/month. However, this includes any contributions to the 国民年金基金 and 付加年金. The ¥68,000 is a combined ceiling across all three, not ¥68,000 for iDeCo alone.

Withdrawal rules — 受給の条件

This is where iDeCo gets serious. Unlike NISA, where you can sell and withdraw at any time, iDeCo has strict lock-up rules. Understanding these is critical before committing money.

Standard withdrawal: You can start receiving benefits from age 60, but only if you have been enrolled in iDeCo (or a qualifying pension plan) for at least 10 years. If you have fewer years of enrollment, the earliest withdrawal age increases:

You must begin receiving benefits by age 75 at the latest. Between your eligible start age and 75, you choose when to start withdrawing.

Exceptions that allow early access:

• Disability (障害給付金) — if you become severely disabled (grades 1-2 under the disability pension system), you can receive your iDeCo balance as a disability benefit, tax-free (非課税)
• Death (死亡一時金) — if the account holder dies, the balance is paid to designated beneficiaries as a lump sum. Treated as みなし相続財産 (deemed inheritance) and subject to 相続税 (inheritance tax), but with a ¥5M non-taxable allowance per legal heir
• Lump-sum withdrawal for foreigners leaving Japan (脱退一時金) — under strict conditions (see foreigners section below)

iDeCo for foreigners in Japan — 外国人のiDeCo

iDeCo is available to all residents of Japan enrolled in the public pension system (国民年金 or 厚生年金), regardless of nationality. If you have a valid visa and are paying into the pension system, you can open an iDeCo account. However, there are several foreigner-specific issues you need to understand.

What happens if you leave Japan?

This is the critical question. When you leave Japan and lose your pension enrollment status, you cannot continue contributing to iDeCo. Your account enters a dormant state called 運用指図者 (operation-only status) — your existing investments remain in the account and continue to be managed, but you cannot add new money. You also continue paying the monthly administrative fees (typically ¥66/month to the National Pension Fund Association).

Option 1: Leave money in iDeCo until age 60 — Your investments stay in the account, continue growing (or declining), and you can withdraw when you reach the eligible age. You'll still pay administrative fees. This makes sense if you have a substantial balance and plan to eventually return to Japan or can wait until age 60.

Option 2: 脱退一時金 (lump-sum withdrawal) — Under very specific conditions, foreigners who leave Japan can withdraw their iDeCo balance early. As of 2026, the requirements are:

• You are a non-resident of Japan (lost your 住民登録)
• You are no longer enrolled in the Japanese pension system
• Your iDeCo contribution period was less than 5 years, OR your asset balance is ¥250,000 or less
• You have lost eligibility to receive disability benefits
• You apply within 2 years of losing pension enrollment

The 5-year contribution rule is the biggest hurdle. If you've been contributing for more than 5 years and your balance exceeds ¥250,000, you cannot take a lump-sum withdrawal — the money stays locked in iDeCo until you reach withdrawal age, even if you've left Japan entirely.

Can you transfer iDeCo to an overseas pension?

No. There is no mechanism to transfer iDeCo assets to a foreign pension plan (401(k), UK workplace pension, Australian super, etc.). Japan's pension system has social security agreements (社会保障協定) with many countries that allow contribution periods to be counted across borders for public pension eligibility, but these agreements do not cover iDeCo. iDeCo is a private defined-contribution plan, not a public pension benefit.

Interaction with the pension refund (脱退一時金)

Many foreigners leaving Japan claim the public pension refund (脱退一時金) — a partial refund of their 厚生年金/国民年金 contributions. This is a separate process from iDeCo withdrawal and one does not affect the other. However, be aware that once you claim the public pension refund, you permanently give up the contribution periods covered — which could affect your eligibility under social security agreements. Consult with a pension specialist before making both decisions.

Decision framework: which should you use? — どちらを選ぶべきか

Here's a straightforward decision framework based on your situation. Work through it step by step:

The short version

Frequently Asked Questions — よくある質問