Anniversaries/March 31
From Sonic Retro
March 31 (add)
- 1999 — Issue #9 of the Sonic Super Special comic series is released in North America.
- 2006 — Sonic Mega Collection Plus is released for the PC in Europe.
- 2009 — Sonic and the Black Knight is released for the Wii in Australia.
- 2010 — Issue #211 of the Sonic the Hedgehog comic series by Archie Comics is released in North America.
- 2016 — Sonic the Hedgehog CD is released for Apple TV in North America.
- 2020 — "Dokutā Egguman Sansen!", the 56th episode of Sonic X, airs in Japan.
- 2022 — The Sonic the Hedgehog 2 film premieres in theaters in Australia.
- 2023 — The Murder of Sonic the Hedgehog is released for Steam worldwide.