Bonnie and Toy Chica appear in this room as they both use the Left Air Vent in order to reach The Office. Mangle may also appear here in the bottom right corner of the screen, but it only enters the Right Air Vent in Party Room 2.
Party Room 1 is a small, enclosed room, where birthday parties appear to be held at the rebuilt Freddy Fazbear's Pizza. The room has a black and white, shiny, checkered floor and smooth walls with green and blue checkered stripes, as well as a confetti pattern on the walls' top half. The walls also have some sort of dark substance smeared on them in various places close to the floor. It appears to be ventilated by the Left Air Vent located on the left wall, which animatronics will enter to get to The Office.
The room has two large tables topped with a white tablecloth with a multi-colored confetti pattern, and two neat rows of striped, multi-colored party hats. The walls appear to have posters of the main characters, such as Toy Freddy, Toy Bonnie, and Toy Chica. The posters have the animatronics' "catchphrases" on them: Toy Bonnie's reads "LET'S ROCK!", Toy Chica's reads "LET'S EAT!", and Toy Freddy's has him winking while seemingly pointing at the viewer with his microphone, with the words "PARTY TIME" at the top, and "U READY?" at the bottom.
There is a mostly obscured banner on the ceiling, close to the wall. It is assumed this is a "HAPPY BIRTHDAY" banner, like in all the other Party Rooms, as the word "HAPPY" can be made out. A strand of paper dolls hangs from the ceiling in front of the banner.
- This is the only Party Room that Toy Bonnie doesn't visit.
- The air vents seem to be completely open, which is strange, as children could easily climb into them. Realistically, they would have some kind of panel which allows air to flow, but stops children from climbing into the vents for safety reasons.
- Toy Chica's party poster says "LET'S EAT!" despite the fact that her bib reads "LET'S PARTY!", possibly referring to the old Chica's bib, which read "LET'S EAT!!!"
- Despite this room being the only way to access the Left Air Vent, BB is not visible here before crawling through the Left Air Vent, likely because he stays hidden throughout his path to The Office.
- Toy Freddy's poster on the left wall doesn't use grammar, as it should say 'Are you ready?' instead of "U Ready?"