How many days outside Japan are allowed for naturalization?

There is no fixed legal limit, but in practice long trips over 3 months or annual totals exceeding roughly 150 days may negatively affect the evaluation of continuous residence for naturalization.

Naturalization in Japan: Time Outside the Country Rules & 5-Year Residence Guide (2025)

[Latest Update | Dec 5, 2025]

The Japanese government is currently reviewing the entire naturalization system, including eligibility requirements, as part of the “Comprehensive Foreign Policy Measures” scheduled for January 2026. In particular, the operation of the “five years or more of residence” requirement is expected to become stricter, possibly approaching the 10-year standard used for permanent residence.

What Does the Tightening of Naturalization Requirements Mean? Latest Trends and Expert Analysis

If you are considering applying for naturalization, we strongly recommend applying early with professional support.

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How many days spent outside Japan are acceptable when applying for naturalization?

We often receive questions such as, “I want to apply for naturalization in the future, but I’m worried about the number of days I’ve spent outside Japan,” or “How do past overseas business trips or temporary returns affect my application?” Under the Nationality Act, one of the basic requirements for standard naturalization is “having continuously maintained a domicile in Japan for five years or more.” However, the law does not specify a concrete numerical limit for time spent outside Japan.

In practice, however, excessive time abroad may lead authorities to conclude that you are not ‘continuously residing in Japan,’ which can become a negative factor in naturalization screening. This page clearly explains how time spent outside Japan is evaluated, commonly used practical guidelines, cautionary cases, and countermeasures—based on actual practices as of 2025.

Contents

Naturalization and the Requirement of “5+ Continuous Years of Residence in Japan”
Common Practical Guidelines for Time Spent Outside Japan
Differences in Evaluation by Reason for Travel: Business vs. Personal
Risks and Countermeasures When Time Abroad Is Excessive
Managing Time Outside Japan with Future Naturalization in Mind
Consult a Professional If You Are Concerned About Time Spent Abroad
Related Pages Often Read Together with Naturalization Applications
Google Reviews

1. Naturalization and the “5+ Continuous Years of Residence in Japan” Requirement

One of the core requirements for standard naturalization is having continuously maintained a domicile in Japan (lawful residence status) for five years or more up to the time of application. Here, “domicile” means more than a temporary stay—it refers to Japan being your main base of daily life.

This is where the word “continuously” becomes closely tied to time spent outside Japan. It does not mean you must never leave Japan for five years, but long absences or an excessively high number of days abroad within a year may be treated as an interruption of residence.

In other words, naturalization screening commonly reviews the following two points together:

The five-year residence period (domicile requirement)
Time spent outside Japan during that period (whether there were long or frequent trips abroad)

Based on these factors, authorities assess whether you have continuously lived in Japan as your primary base of life.

2. Common Practical Guidelines for Time Spent Outside Japan in Naturalization

As noted above, there is no statutory “hard limit” written into the law; these are practical guidelines used in Legal Affairs Bureau operations. Interpretations may vary by bureau and examiner, but the following thresholds are commonly referenced in practice.

1. Guideline for the length of a single trip

Less than 3 months (about 90 days) per trip: often not a major issue in many cases.
3 months or more per trip: the prior period may no longer be treated as “continuous,” and the count may be considered reset.

If you have been outside Japan for more than three months due to overseas assignment, childbirth, temporary return, etc., exceptions may be possible depending on the circumstances. However, in such cases you are often asked to submit additional explanations and supporting documents, and further interviews may be required.

2. Guideline for total days abroad per year

Even when each trip is short, too many total days abroad in a year may raise doubts about whether Japan is truly your main base of life. In practice, the following ranges are often used as rough benchmarks:

Up to 100 days per year (total): often viewed as a relatively safe range.
About 100–150 days per year: requires careful assessment; you may be asked to provide explanations and evidence.
150–180 days or more per year: higher risk of being viewed as having weak residence reality, leading to reset risk or refusal risk.

These are only general benchmarks, but “3+ months per trip” or “150+ days per year” are widely recognized as lines that require particular caution.

3. Evaluation Differences by Reason for Travel: Business vs. Personal

A key feature of naturalization screening is that the evaluation can change depending on the reason for travel, even if the number of days abroad is the same. Let’s look at typical examples.

1. Overseas business trips or temporary assignment by employer instruction

Trips such as overseas business travel or temporary assignment ordered by your employer—travel that is not fully within your personal control—tend to be judged more flexibly than purely private travel.

Even so, it is important to explain that the travel was unavoidable by preparing documents such as:

Business trip orders / appointment letters / overseas assignment notices
Employer certificate (period, purpose, workplace/location, etc.)
Proof of continued employment such as pay slips and withholding slips

With these materials, you can demonstrate that you maintained your living base in Japan and traveled abroad only as necessary for work.

2. Personal travel or temporary return to your home country

By contrast, if private travel or frequent temporary returns result in a high number of days abroad, the residence requirement may be evaluated more strictly. In particular, cases such as:

Repeated long overseas trips for tourism
Spending an extended period in your home country every year, reducing time actually lived in Japan

may lead examiners to question whether your true main base of life is in Japan.

3. Special circumstances such as illness, caregiving, or childbirth

If you had to remain abroad for an extended period due to unavoidable circumstances such as illness, caregiving, or childbirth (your own or a family member’s), it is effective to prepare and explain carefully with documents such as:

Medical certificates / hospitalization records
Maternity and child health handbook / birth certificates
Official documents showing caregiving necessity

Even in such cases, extremely high totals or very frequent travel can still be judged strictly. However, providing a clear explanation with evidence can significantly improve the outcome compared to providing no explanation at all.

4. Risks and Countermeasures When Time Spent Outside Japan Is High

Having spent many days outside Japan in recent years does not automatically make naturalization impossible. However, applying at the wrong time may result in refusal or a recommendation to withdraw the application, so advance review is essential.

1. First, organize your “travel history for the past five years”

In a naturalization application, you must list your entry and exit history for the five years preceding the application date in detail. Use passport entry/exit stamps and official disclosure of immigration records to整理 the following points:

The period of each trip (from YYYY/MM/DD to YYYY/MM/DD)
Number of days for each trip
Total days abroad for each year
Reason for travel (business trip, travel, temporary return, childbirth, etc.)

Creating this list alone often makes it clear which years are “safe” and which years require extra caution due to higher time abroad.

2. Adjust the application timing to avoid a reset

If, within the past five years, there are years that include:

A single trip of three months or more
Total annual time abroad of 150 days or more

one option is to wait until those years fall outside the five-year review period. Practically speaking, applying after five years have passed since the most problematic travel allows the “5+ continuous years” count to be rebuilt.

3. Strengthen other factors in addition to time abroad

If your time abroad is relatively high, it becomes even more important to carefully prepare the following:

Full payment of resident tax and income tax (confirm no arrears or installment plans)
Pension and health insurance contributions (resolve any non-enrollment or non-payment early)
Stability of employer, employment type, and annual income
Family ties and housing situation in Japan (home ownership, long-term lease, etc.)

Naturalization is not judged by time abroad alone; authorities assess your overall living foundation and ties to Japan. The more uncertain your travel history, the more important it is to strengthen positive factors in other areas.

5. Managing Time Spent Outside Japan with Future Naturalization in Mind

If you are not applying yet but plan to obtain Japanese nationality in the future, keeping the following points in mind from now on can provide peace of mind:

Keep each trip abroad under three months whenever possible
Aim to keep total annual days abroad within 100 days
If your job involves long or frequent overseas travel, always keep supporting documents as evidence
Keep old passports even after renewal or reissuance
If there is a year with heavy travel, reduce travel in subsequent years to restore balance

Time spent outside Japan cannot be changed after the fact. Therefore, from the moment you begin considering naturalization, being mindful of your travel days and managing entry/exit in a planned manner is the shortest path to a smooth application.

6. Consult a Professional If You Are Concerned About Time Spent Abroad

Even with the same number of days abroad, naturalization outcomes can vary greatly depending on factors such as the reason for travel, family composition, employer and income, and overall residence history. Relying solely on general online information can lead to giving up on an application that was actually viable—or applying too early and facing an unfavorable result.

If you are researching “naturalization and time spent outside Japan” and feel uncertain, we recommend first organizing your travel history and residence status, then consulting a professional for a case-specific assessment.

Our office has extensive experience supporting naturalization applications for individuals with frequent overseas travel, business trips, or temporary returns. We provide tailored advice on optimal application timing and necessary explanatory documents for each case. Please feel free to contact us.