How to change your name in Japan

After marriage

What marriage does to your surname depends on who you married. Two Japanese nationals must share one 氏 (uji, surname): the couple choose the husband's or the wife's on the 婚姻届 (kon-in todoke, marriage notification), and the register cannot record a married couple with two surnames (民法 Civil Code, Art. 750). A Japanese national who marries a foreign national keeps their own surname by default; the marriage changes nothing (Ministry of Justice Q&A; Iwakuni City). If you want your foreign spouse's surname, file a 外国人との婚姻による氏の変更届 (notification of surname change on marriage to a foreign national) at your 本籍地 (honseki, registered domicile) or your current municipality within six months of the marriage, counted from the day the marriage was formed and including that day; no court is involved (戸籍法 Family Register Act, Art. 107(2); Osaka City). It may be filed with the marriage notification or at any time inside that window. The surname you take has to be the one your spouse actually bears: a 複合氏, a compound of your surname and theirs, needs the family court's permission first (Iwakuni City). Past six months the same change needs the court's permission too, under the ordinary 氏の変更許可 route below. If you have children in your register, a new register is created with you as its head under the new surname, and they join it by 入籍届 (nyuseki todoke, notification of entry). Your foreign spouse never becomes a member of your register; their name, date of birth and nationality are written into your own entry as the record of the marriage.

After divorce

A surname taken on marriage falls away on divorce without anyone asking. The spouse who changed their surname to marry returns to their pre-marriage surname the moment a divorce by agreement takes effect (民法 Civil Code, Art. 767(1)), and the same rule is applied to a divorce given by a court (Art. 771). The register follows: you go back into the register you were in before the marriage, or a new one is made for you if that register has been closed or you ask for your own (戸籍法 Family Register Act, Art. 19). If you would rather keep the married surname — most people who have built a working life or children's school records under it do — file a 離婚の際に称していた氏を称する届 (notification to use the surname held at the time of the divorce, the 婚氏続称 route) within three months of the divorce, counting the day of the divorce itself (Art. 767(2); 戸籍法 Art. 77-2; Osaka City). For a divorce by agreement the three months run from the day the 離婚届 is filed; for a court divorce, from the day the judgment became final. You may hand it in together with the divorce notification. Miss the window and the married surname is only available again through the family court. The mirror case is the marriage to a foreign national: someone who took the spouse's surname under Art. 107(2) may go back to the surname they held before that change by filing a 外国人との離婚による氏の変更届 within three months of the divorce, the annulment or the spouse's death, again without a court (戸籍法 Art. 107(3); Osaka City). Widowhood is different from divorce: a surviving spouse is not moved back at all, and returns to the pre-marriage surname only by filing a 復氏届 (fukushi todoke), for which no deadline is set (民法 Art. 751; 戸籍法 Art. 95; Osaka City). Children keep the surname they had; a child who wants the surname of the parent they now live with applies to the family court for 子の氏の変更許可, ¥800 in revenue stamps per child, and then files an 入籍届 (民法 Art. 791; Courts in Japan). Whatever you file, the passport office works from the register, so order a 戸籍謄本 showing the new state of things before you apply for a passport.

For any other reason

Outside marriage and divorce, changing a name in Japan is a court matter, and the surname and the given name are two different cases. To change a 氏 (surname) you need やむを得ない事由, unavoidable circumstances, which the courts define as not changing it causing 著しい支障, serious obstruction, in your social life; the 筆頭者 (head of the register) and their spouse apply together to the family court for where they live, with ¥800 in revenue stamps, the postage that court sets, a full copy of the register, evidence of the reason, and the written agreement of everyone aged 15 or over in the register (戸籍法 Art. 107(1); Courts in Japan). The bar is high because a surname carries the whole register with it. A 名 (given name) is easier: it needs 正当な事由, a justifiable reason, defined as the name causing 支障, trouble, in your social life — a different everyday name used for years, a reading nobody can manage, a name that invites ridicule, a name shared with someone in the same household — and mere personal taste, feeling or religious preference is expressly not enough. The person themselves applies, or a legal representative for a child under 15, to the family court for where they live, again with ¥800 in revenue stamps and the court's postage (戸籍法 Art. 107-2; Courts in Japan). Neither court publishes how long a decision takes. Permission is not the change: once the 審判 (decision) is final, take its certified copy and, for a surname, its 確定証明書 (certificate of finality) to your 本籍地 or current municipal office and file the 氏の変更届 or 名の変更届 there (Osaka City). Since 26 May 2025 the register also carries the 振り仮名 (furigana, the reading) of your name, and the one-off window to notify your own reading closed on 25 May 2026; a reading is now changed the same way as the name it belongs to, by family court permission and then a notification (戸籍法 Arts. 107-3 and 107-4; Osaka City). A foreign national living in Japan has no 戸籍, so none of this applies to them: their name changes under their own country's law, and the 住民票 (residence record) follows the passport.

If you married outside Japan

Japan looks at two questions separately. Whether each of you was free to marry is judged by each person's own national law; how the marriage was performed is judged by the law of the place where it was celebrated (法の適用に関する通則法 Act on General Rules for Application of Laws, Art. 24(1) and (2)). A marriage performed under another country's or state's formalities — its licence, its officiant, its certificate — is valid in form in Japanese eyes if that place is treated as the place of celebration. A Japanese national who marries that way must then report it: send the original marriage certificate, issued within the last three months, with a Japanese translation naming the translator, to a Japanese embassy or consulate, or to the municipal office of your honseki, within three months of the marriage (戸籍法 Family Register Act, Art. 41; Ministry of Justice Q&A; Maebashi City). The report is a 婚姻届, filed by the Japanese spouse alone; it needs no witnesses because the marriage already exists. None of the official lists we read asks for an apostille, though depending on what the certificate says an office may also want the foreign spouse's birth certificate with a translation, or a passport. A divorce obtained abroad is reported the same way: a divorce made under that country's formalities goes in within three months under Art. 41, while a divorce given by a foreign court is reported by the party who brought the case within ten days of the judgment becoming final, with a copy of the judgment and its proof of finality attached (戸籍法 Arts. 77 and 63; Osaka City). One point is unsettled. Art. 24(3) says a form valid under one party's national law is good enough, except where the marriage is celebrated in Japan and one party is Japanese — there only Japanese formalities count. We found no Ministry of Justice or municipal statement on whether an online ceremony run by an officiant in another country, while both of you sat physically in Japan, is celebrated there or in Japan. If you are Japanese and were in Japan for the ceremony, ask the 戸籍 (koseki, family register) section of your honseki office before you rely on the foreign certificate. If the office declines to record it, a Japanese 婚姻届 signed by two adult witnesses creates the marriage under Japanese law on the day it is accepted, and two Japanese nationals may file that form at a consulate or by post to the honseki office even from abroad. If both spouses are foreign nationals, Japan has no report to file at all.

Build my checklist for Japan

The steps above become a checklist you can work through and tick off, with the office, the form and the fee on every one. It is free, and it is the whole plan if Japan is where your records are.

If you live in the United States

If you are a Japanese citizen living in the United States, your American records change with the US checklist: Social Security, your state licence, banks and employer. Your Japanese side is the same law as at home, done through the nearest Japanese embassy or consulate. After a marriage, report it there within three months of the ceremony with the certificate and a Japanese translation naming the translator, and file the 外国人との婚姻による氏の変更届 within six months if you want your spouse's surname. After a divorce, the same consulate takes the report — three months for a divorce made under a US state's formalities, ten days from finality for one given by a US court, with the decree and its proof of finality — and it takes the 離婚の際に称していた氏を称する届 or the 外国人との離婚による氏の変更届 inside their own three months. A US court order changing your name is the one case where the consulate cannot finish the job: it changes your American records, but it does not touch your 戸籍, and the Japanese change still needs the family court — the one for your last address in Japan, or the Tokyo Family Court if you never had one. Once the register shows the new name, apply at the consulate for a passport in it; the consulate sets its own fee in dollars. Plan the order so that the name on your Japanese passport and the name on your US documents agree, because the airline checks the passport.

Your US records, from Social Security to your state license and the everyday accounts, change with the US checklist; it prepares each form and letter in the order the agencies check them.

Change Your Name is a self-help form-preparation service, not a law firm; this page is general information about Japan, not legal advice.