Ace Combat X: Skies of Deception (エースコンバットX スカイズ・オブ・デセプション Ēsu Konbatto Ekkusu Sukaizu Obu Desepushon) is the seventh Ace Combat game and the first PlayStation Portable game in the franchise. It was released worldwide in 2006.
Ace Combat X introduced new mechanics such as tuning aircraft parts as well as the Multi-Purpose Gauge for mission objectives. The game also expanded on the ability to choose alternate missions in some prior games. Players can choose which missions they want to complete next, or skip some missions entirely. These decisions change what enemies the player will face.
Ace Combat X, like all other PSP games, could be converted to digital format in Japan for the PS Vita. As of 2016, this was no longer available. Players who already owned the digital version of Ace Combat X could still re-download it, but new players will not be able to acquire it.