Before being activated, the Warp Door appears as a simple, dark doorframe which the party cannot see through. After activation, each Door gains a flickering glow emanating from underneath it and the party can use it to access any other Warp Door that they have already visited.
- In the Field in the room east of Seam's shop.
- In the Forest. Mr. Elegance, sometimes accompanied by the Tutorial Master, introduces the party to its mechanics.
- Bake Sale, to the west of the path to the smith Malius.
- At the end of the Forest just before the entrance to Card Castle. When the party first passes the door, it is inactive and going east leads to two bullet-hell rooms guarded by Rudinn Rangers. When returning from the castle entrance, these areas are skipped and the now-active door is in the next room to the west.
- The Warp Door has a sprite reused from Undertale, where it was used as the door to Sans's room. Its sprite also resembles the door to Undyne's room in the same game.