Getting married in Japan
No status of residence is required to get married in Japan; it is possible as a tourist.
The act of getting married in Japan is the submission/acceptance of a marriage registration document (called konin todoke / 婚姻届), together with supporting documents, at the municipal office. Many couples have a wedding ceremony too, but the konin todoke is not normally a part of the ceremony; most couples are legally married at the time of their wedding ceremony.
The konin todoke is a simple document with basic details about the couple. Stylised versions of the form can be found online and in magazines; these are valid for submission. The form requires two witnesses, who can be family members. Note that the witnesses witness the couple inputting details on the form; they do not witness the couple’s submission of the form.
Where one or both of the couple reside in Japan, the konin todoke must be submitted to the municipal office of the place of residence. Submission of documents to register marriages (and births, and deaths) can be done 24/7/365; there will be a system in place to deposit the document out of standard opening hours. Whether submitting in-hours or out-of-hours, foreign nationals are advised to visit their municipal office in advance to discuss the paperwork requirements, including any translation requirements, and whether such translations can be done informally or whether they need to be done by a professional translator. If getting married whilst a tourist, check how the municipal office would like you to fill out the address field on the konin todoke – they may just require ‘overseas’ rather than a specific address or, indeed, a specific country.
The supporting documents will include a certificate of no-impediment for foreign nationals. This is usually obtained at your country’s embassy or consulate in Japan, and the certificate of no impediment might be called something different by your embassy/government, eg for UK nationals, the required certificate is either an affirmation (non-religious) or an affidavit (religious).
A birth certificate may also be required.
Marriage certificates are not issued automatically because the family register (koseki tohon / 戸籍謄本) is king in Japan. It is strongly recommended to apply for at least one certificate of notification of marriage (kekkon-todoke juri shōmeisho / 結婚届受理証明書) when submitting your marriage paperwork. Together with an official translation, this should serve as proof of marriage for most purposes in most jurisdictions. (Such a document can be obtained at a later date, but it might be burdensome to order from afar, in time or distance.)
If one partner is Japanese, the non-Japanese spouse will be added as a note on the Japanese national’s family register. (This will happen even if the non-Japanese national is registered as the head of the household.)