The 35th anniversary of the Sonic the Hedgehog series, also known as Forever Fast, is a year-long celebration held throughout 2026 to commemorate 35 years since the release of the original Sonic the Hedgehog in 1991. The campaign spans the wider franchise, with anniversary activities encompassing video games, comics, animation and other media, music, merchandise, concerts, exhibitions, collaborations, promotional events and community-focused activities.

Sonic the Hedgehog 35th Anniversary 2026 Wall Calendar with 4 Bonus Notecards surfaced ahead of its planned August 2025 release.//www.amazon.com/dp/1419784390?ref=cm_sw_r_ffobk_cp_ud_dp_ZD8EGT82N3AGPQNPMMER&ref_=cm_sw_r_ffobk_cp_ud_dp_ZD8EGT82N3AGPQNPMMER&social_share=cm_sw_r_ffobk_cp_ud_dp_ZD8EGT82N3AGPQNPMMER&bestFormat=true" work="Amazon" access-date="9 June 2025"

SEGA formally began the anniversary campaign on 15 January 2026, launching a dedicated anniversary website and releasing a commemorative trailer looking back across the history of the series.//www.youtube.com/watch?v=kJJZ6Cq9tqg" work="YouTube" author="Sonic the Hedgehog" date="15 January 2026" The celebrations were planned to continue throughout the year, with initiatives focused on bringing fans together through new and existing games, digital projects, community gatherings, retail and brand partnerships, limited-edition products, exhibitions, live performances and other anniversary experiences.

Takashi Iizuka described the anniversary's various projects as sharing a common theme of allowing people to have fun together and experience games with their friends. By August 2026, Iizuka stated that further surprises for the 35th anniversary were still to come, while additional games, collaborations, merchandise and events continued to be announced as the campaign progressed through the latter half of the year.