The Japan Pension Service has announced the issuance and mailing schedule for the 2026 (Reiwa 8) social insurance premium (National Pension premium) deduction certificates ^[1]. These certificates will be sent to anyone who paid National Pension premiums during 2026, covering the period from January 1 to December 31, 2026 ^[1]. The certificate proves the amount of National Pension premiums paid during the year and is required when claiming the social insurance premium deduction in year-end tax adjustment or income tax returns, through attachment of the certificate or payment receipts ^[1].

For those who paid premiums between January 1 and September 30, 2026, electronic data certificates will be sent successively from mid to late October 2026, while paper certificates will be mailed successively from late October to early November 2026 ^[1]. For those who paid premiums between October 1 and December 31, 2026 (excluding the first group), electronic certificates will be sent successively from late January 2027, and paper certificates will be mailed in early February 2027 ^[1]. People who are due to receive the electronic data version will not also receive a paper copy by mail ^[1].

Electronic certificates can be used for e-Tax filing provided through the National Tax Agency, and recipients should check the guidance on receiving tax-related notices via Mynaportal for details on the electronic delivery service ^[1].

The social insurance premium deduction applies to premiums paid for oneself or for a spouse or other family members, including National Pension and National Health Insurance ^[1]. The Japan Pension Service clarified that it does not issue these certificates to employees covered only by employee pension schemes, such as Employees' Pension Insurance or mutual aid associations, because those premium deductions are calculated and reported by employers directly to municipalities and tax offices ^[1]. However, anyone enrolled in an employee pension scheme who also paid National Pension premiums at least once during 2026 will still receive a certificate for that National Pension payment ^[1].

The Japan Pension Service also noted that, for tax returns filed on or after January 1, 2027 covering the 2026 tax year, filers may attach a statement listing the details from the certificate or receipts instead of the original documents, though this substitution is not permitted for year-end adjustment ^[1]. Further details on the 2026 certificate issuance are provided in a related notice from the Japan Pension Service ^[2].

Source credit 出典：「令和8年分社会保険料（国民年金保険料）控除証明書の送付予定をお知らせします」（日本年金機構）（https://www.nenkin.go.jp/oshirase/taisetu/kojin/2026/202609/0924.html）を加工してJapan News (j.apan.news)が作成 出典：「令和8年分社会保険料（国民年金保険料）控除証明書の発行について」（日本年金機構）（https://www.nenkin.go.jp/oshirase/taisetu/kojin/2026/202610/1009.html）を加工してJapan News (j.apan.news)が作成 This article is Japan News's own English summary of the Japanese original. It has been translated and edited by Japan News; it is not an official translation, and the Japan Pension Service did not write or review it.