The 721 series (721系) is an AC electric multiple unit (EMU) operated by Hokkaido Railway Company (JR Hokkaido) on Sapporo area suburban services in Hokkaido, Japan since 1988.

[2] The trains were built jointly by Hitachi, JR Hokkaido (Naebo Factory), Kawasaki Heavy Industries, and Tokyu Car (Yokohama).

[4] Withdrawals of the 721 series commenced in 2023 with 721-3000 series set F-3016 being scrapped as of August.

[5] This continued the following year with sets F-4 and F-3015 being sent to Naebo for scrapping in April 2024.

[6][7] In April 2024, JR Hokkaido announced that it will replace the 721 series with additional 733 series trains on Chitose Line Airport services.