Planetarian: The Reverie of a Little Planet
"Planetarian" was released on November 29, 2004 via download over the Internet playable on Windows PCs, and was first made available only to Yahoo! Japan Broadband users. The game was opened up for general sale on December 6, 2004. Key released a CD-ROM version for Windows PCs on April 28, 2006 in limited and regular editions. An updated version of "Planetarian" compatible for Windows Vista PCs was released by Key on July 31, 2009 in a box set containing five other Key visual novels called Key 10th Memorial Box. Another updated version compatible for Windows 7 PCs called "Planetarian: The Reverie of a Little Planet Memorial Edition" was released on April 30, 2010. The "Memorial Edition" also came bundled with the three previously released "Planetarian" drama CDs. An HD edition for Windows was released on July 29, 2016. "Planetarian" was released on Steam by Sekai Project in English for Windows on September 12, 2014, with later support planned for macOS and Linux devices. The Steam release was updated on September 17, 2014 to allow the user to switch to the original Japanese version of the game.
Planetarian: The Reverie of a Little Planet
A consumer console port of the game was released for the PS2 on August 24, 2006 by Prototype. A version playable on FOMA mobile phones was released by Prototype through VisualArt's Motto on November 24, 2006. A limited edition version of "Planetarian" developed by Prototype playable on the PlayStation Portable (PSP) was available for purchase between February 28 and March 1, 2009 at Key 10th Memorial Fes, an event held in commemoration of Key's ten-year anniversary. A downloadable version of the PSP release via the PlayStation Store was released by Prototype on August 24, 2009. Prototype again sold the PSP version at their Prototype Fan Appreciation 2010 event on May 30, 2010. The PSP version was re-released on May 12, 2011 as a fundraising release for the 2011 Tōhoku earthquake and tsunami. A mobile app version playable on Android and iOS devices was released on November 30, 2011. An updated iOS version released in January 2013 includes support for English readers. A Nintendo Switch version is planned to be released by Prototype in early 2019.