Becoming a U.S. Citizen as a Korean National (2026): N-400 Eligibility, Fees, and What Happens to Your Korean Nationality

1. Am I Eligible to Apply for U.S. Citizenship?

Under INA §316 and §319(a), an applicant generally must:

• be at least 18 years old when filing;
• have been a lawful permanent resident for 5 years, or 3 years if married to and living with a U.S. citizen spouse who has been a citizen for that whole period;
• have continuous residence in the U.S. for that period;
• have physical presence in the U.S. for at least half of it (30 months on the 5-year path, 18 months on the 3-year path);
• have lived for at least 3 months in the state or USCIS district where they file;
• show good moral character for the statutory period; and
• pass the English and civics tests, unless an exemption applies.

Continuous residence and physical presence are different tests

Physical presence counts the days you were actually in the United States. Continuous residence asks whether you kept the U.S. as your home. A single trip abroad of more than 6 months (but less than a year) can raise a presumption that continuous residence was broken, which you may be able to rebut with evidence such as keeping your job, home and tax filings here. A trip of one year or more generally breaks it. Long or frequent stays in Korea are worth mapping out date by date before you file.

Good moral character

USCIS reviews the statutory period (and can look further back) for criminal history, unpaid taxes or unfiled returns, false claims, and prior immigration issues. Arrests and citations should be disclosed even if they were dismissed. These are the points we review first.

English exemptions for long-term older residents

Applicants who are 50 or older with 20 years as a permanent resident (“50/20”), or 55 or older with 15 years (“55/15”), are exempt from the English requirement and may take the civics test in Korean with an interpreter. Applicants 65 or older with 20 years as a permanent resident (“65/20”) also receive special consideration on the civics test. See our N-400 interview preparation guide.

2. When Can I File? The 90-Day Early-Filing Rule

Start from the “Resident Since” date on your green card. Add 5 years (or 3 years on the marriage path), then count back 90 days. That is the earliest date USCIS will accept your N-400. USCIS publishes an early-filing calculator on its website. An application filed even one day too early is denied, and the filing fee is generally not refunded, so it is worth confirming the date before you file.

The residence and physical-presence requirements are still measured over the full period, so trips abroad near the filing date matter too.

3. What Does It Cost in 2026, and What Might Change?

The current USCIS filing fee for Form N-400 is $760 for paper filing or $710 for online filing, with biometrics included. A reduced fee of $380 is available to applicants whose household income is between 150% and 400% of the federal poverty guidelines, and fee waivers are available in limited circumstances.

On June 23, 2026, the Department of Homeland Security published a proposed rule (Federal Register document 2026-12542) that would raise the N-400 fee to $1,330 (paper) or $1,280 (online) and eliminate the reduced fee and fee waivers for most applicants. The public comment period closed on August 24, 2026. The rule has not been finalized. If it is finalized, the new fees would apply from its effective date; until then, current fees apply. Confirm the fee on uscis.gov/n-400 before filing.

4. What Happens to My Korean Nationality When I Become a U.S. Citizen?

Automatic loss on voluntary naturalization

Under Article 15(1) of the Korean Nationality Act, a Korean national who voluntarily acquires a foreign nationality loses Korean nationality as of the date of acquisition. For an N-400 applicant, that is the day you take the Oath of Allegiance. No separate renunciation filing with Korea is needed for the loss to take effect.

Report the loss (국적상실신고)

Article 16 requires a person who has lost Korean nationality to report it so that Korean records, including the family-relation register (가족관계등록부), are updated. Orange County residents generally file this report through the Consulate General of the Republic of Korea in Los Angeles. Keep a copy of your Certificate of Naturalization for the filing.

Travel to Korea

After you naturalize, travel to Korea on your U.S. passport. Your Korean passport is no longer valid for you once Korean nationality is lost.

Exceptions are narrow

Article 15(2) allows certain people who acquire a foreign nationality through specific events (for example, some cases of marriage to a foreign national, adoption, or recognition by a foreign parent) to keep Korean nationality if they notify Korea of their intent within 6 months. These exceptions are fact-specific. Naturalizing through Form N-400 is generally treated as a voluntary acquisition, so do not assume an exception applies without advice.

Options after naturalization

Former Korean nationals may qualify for the F-4 (재외동포, Overseas Korean) visa, which allows long-term stay and most work in Korea. Certain former Korean nationals age 65 or older may apply to restore Korean nationality (국적회복) while keeping U.S. citizenship by pledging not to exercise their foreign nationality in Korea (외국국적불행사서약). Eligibility is decided by the Korean Ministry of Justice.

The U.S. side

The U.S. Oath of Allegiance includes renunciation language, but U.S. law does not require you to take any action with Korea. Korea’s own law determines your Korean status.

5. What Should I Do Before Filing?

• Confirm your 5- or 3-year date and the 90-day early-filing window.
• List every trip abroad during the statutory period, with dates, and flag any trip over 6 months.
• Confirm your federal and state tax returns are filed for the period.
• Gather records for any arrest, citation or court case, even if dismissed.
• Men who lived in the U.S. between ages 18 and 26: check Selective Service registration.
• Confirm any child-support obligations are current.
• Consider Korea-side matters before naturalizing, such as property, bank and securities accounts, the family-relation register, and, for men, military-service records. Get advice on both systems.

When you are ready to prepare for the interview itself, see our N-400 interview guide and our naturalization services page.

6. Frequently Asked Questions