Pokémon Platinum, the official sequel to Diamond/Pearl, was released in the Americas on March 22, 2009 and in Europe on May 22.

The game features Giratina as its mascot and introduces its Origin Forme, a new form of the Pokémon as seen in the movie Giratina and the Sky Warrior. However, once the player comes out of the Distortion World, Giratina returns to its original "Altered Forme" as seen in Diamond and Pearl. With the use of a new item called the Griseous Orb found in the game, the player can decide which forme it uses. The game's storyline involves the awakening of Giratina, after which the Pokémon opens a portal to the "Distortion World", an alternate dimension in which the normal laws of physics do not apply. Other added features include the Battle Frontier (first introduced in Pokémon Emerald), which in Platinum adds three new facilities: the Wi-Fi Plaza; an arcade area, in which the player can play minigames with other people over the Wi-Fi connection; and the Vs. Recorder which allows players to save and replay videos of battles between friends. Shaymin, which was distributed in Japan as part of admittance to the aforementioned film and in America through a promotion via Toys "R" Us, also gained a new form in Platinum, the Sky Forme. When traded to Diamond or Pearl from Platinum, it will transform from its Sky Forme back to its regular form, the Land Forme. With the use of a new item in Platinum, the Gracidea Flower (which can be unlocked after obtaining the event Shaymin), Shaymin can be changed between its two forms. When the special Regigigas that is given out with a pre-order ticket for Giratina to Sora no Hanataba: Shaymin is traded from Diamond or Pearl to Platinum, it activates an event that makes Regirock, Regice, and Registeel available to catch in Platinum. Like Shaymin, Regigigas was released in America via Toys "R" Us. Additionally, five exclusive forms of Rotom were introduced, all of which are can be unlocked with a Secret Key available for download via Platinum's Mystery Gift function.