Anniversaries/June 20
From Sonic Retro
June 20 (add)
- 1997 — Sonic Jam is released for the Sega Saturn in Japan.
- 2001 — Sonic Adventure 2: Prima's Official Strategy Guide is published in North America.
- 2002 — Sonic Xtreme 2D is released by SSNTails.
- 2003 — Sonic Adventure DX: Director's Cut is released for the Nintendo GameCube in Australia.
- 2007 — Volume 4 of Sonic the Hedgehog Archives is released in North America.
- 2012 — Volume 18 of Sonic the Hedgehog Archives is released in North America.
- 2013 — Sonic Blast is released on the Nintendo 3DS Virtual Console in North America. Tails Adventures is released on the Nintendo 3DS Virtual Console in North America and Europe.
- 2023 — Sonic the Hedgehog Volume 14: Overpowered, a trade paperback, is released in North America.