After Summoner Yuna has abandoned her pilgrimage and decided not to summon the Final Aeon to defeat Sin, the party looks into new ways of tackling the beast. They decide to use the party's airship Fahrenheit to battle Sin in a way no one has ever attempted before. When they manage to penetrate Sin's armor, the party makes their way inside Sin, and toward the center, where Yu Yevon rests. On their way deeper into the beast, the party face Seymour Guado who has been absorbed by Sin, for one final battle. At the center of the gargantuan beast, in Dream's End, the party finally meets Jecht who transforms into Braska's Final Aeon.
- Sea of Sorrow - A haunting, red-tinged sea winding through the landscape, it is traversed through a series of waterfalls and watering blue platforms.
- Garden of Pain - A series of steps leading to a platform, it is where the battle with Seymour Omnis takes place. Once he has been defeated, this area is bypassed on all subsequent trips through Sin. However, the staves will remain.
- City of Dying Dreams - A maze of moving platforms and teleport glyphs which must be navigated. Various side paths lead to treasure chests containing weapons and items.
- Tower of The Dead - As the player approaches what appears to be an exit to the city, a large metal tower descends and blocks their path. Examining a glyph on the side of the tower teleports them to the next area.
- The Nucleus - A surreal environment of crystalline floors and walls; the goal is to touch the colored crystal orbs which moves around the tower at random. The camera angle is always moving, adding to the disorientation. Touching 10 crystals transports you to the next area, but touching the icicles which sprout from the floor will cause a battle to begin.
- Dream's End - A ruined version of Zanarkand's Blitzball stadium with a platform leading to the center of the arena. Here the party meets Jecht and fights Braska's Final Aeon. When it has been defeated, Yu Yevon reveals himself, searching for a new Aeon to possess.
- Sinspawn Genais, Sin (Boss)
- Ahriman x3
- Ahriman, Exoray x2
- Behemoth King
- Demonolith x3
- Gemini (Mace), Gemini (Sword)
- Great Malboro
- Land Worm
- Seymour Omnis, Mortiphasm x4 (Boss)
- Braska's Final Aeon, Yu Pagoda (Boss)
- Valefor, Yu Pagoda (Boss)
- Ifrit, Yu Pagoda (Boss)
- Ixion, Yu Pagoda (Boss)
- Shiva, Yu Pagoda (Boss)
- Bahamut, Yu Pagoda (Boss)
- Anima, Yu Pagoda (Boss)
- Yojimbo, Yu Pagoda (Boss)
- Magus Sisters, Yu Pagoda (Boss)
- Yu Yevon, Yu Pagoda (Boss)
The Dream's End area is the representative arena of Final Fantasy X in Dissidia. Unlike most arenas in Dissidia, Dream's End is only used for the two fights against Jecht: one in Tidus' storyline and the other in Shade Impulse. No other bosses are fought here, though a handful of cutscenes do, including Firion and the Onion Knight's respective conversations with Cosmos.
The arena consists of a ruined Blitzball stadium surrounding a circular platform over a field of lava. A massive replica of Jecht's sword appears on the central platform, much like after defeating Braska's Final Aeon in the original game. Long grind bars run along the outer edge of the arena, connecting the central platform to the ruined "stands" opposite. In the Ω version of the stage the Brave pool increases everytime a character guards, dodges, or lands an attack. When landing an attack the Brave pool increase will be equivalent to the amount of damage the attack dealt.
- The final area of Sin, Dream's End, is actually visible in the opening moments of the game. Once the player fights through the first few battles, they are teleported to Dream's End, where a vision of Jecht stands in the central platform, and a cutscene begins when the player approaches it.