Unrevisitable area

Unrevisitable locations are locations primarily in Mario RPGs that are visited during the main storyline and are inaccessible after a certain point in a game.

Super Mario RPG: Legend of the Seven Stars
Bowser's Keep is locked out for the majority of the game until Mario's party can visit it again via the Royal Bus. The layout of Bowser's Keep is replaced with an extended version upon this second visit. The player can no longer visit Count Down's room in Factory after defeating it.

Paper Mario
After defeating the Koopa Bros., the large jail cell where Mario meets Bombette has its hole patched up and the player cannot revisit it. After defeating Fuzzipede, the player can no longer navigate inside the whale's body. After the eruption of Mt. Lavalava, the bottom of the room just before Lava Piranha's becomes unsuitable for Mario to walk on, preventing the player from accessing the chambers beyond. Madam Merlar's cavern in Shiver Mountain becomes inaccessible after placing the Star Stone in the pedestal outside, causing flights of stairs to rise up and block the entrance.

Mario & Luigi: Superstar Saga
The player cannot revisit Princess Peach's Castle after talking to Bowser to leave for the Beanbean Kingdom. The player can access the Koopa Cruiser only twice: the first visit just before reaching the front of the ship and battling Fawful; the second visit after Joke's End where Luigi navigates through the ship in reverse order before collecting the Beanstar. The Mushroom Kingdom side of Stardust Fields is not accessible after crossing the border to the Beanbean Kingdom. The underground caverns beneath Chucklehuck Woods after defeating Chuckolator cannot be revisited after Luigi interacts with the barrel with Mario inside it. The player cannot revisit Guffawha Ruins after Luigi collects the Crabbie Grass. The S.S. Chuckola cannot be revisited once it heads out to sea and sinks in the Oho Ocean Seabed. The player cannot revisit the caverns where the Jellyfish Sisters teach the Mario Bros. their techniques after collecting both Pearl Beans.

Paper Mario: The Thousand Year Door
The Black Skull cannot be entered inside once Flavio hands the Skull Gem to Cortez. The storage cabin and the rooftops of the Excess Express cannot be revisited after defeating Smorg.

In the Palace of Shadow is a hidden room connected to Gloomtail's chamber that can be accessed by blowing up a wall with Bobbery, which contains a Jammin' Jelly and an Ultra Shroom. Once the player places the Star Key in the pedestal in the Riddle Tower, the floors of the four hallways leading to Gloomtail's chamber become stairs, preventing the player from accessing these rooms.

Puzzle & Dragons: Super Mario Bros. Edition
After defeating Bowser in, the player faces him again with the Koopalings in a multicolored void for the final battle. Once Bowser joins the player's team, the latter area cannot be revisited.