The RPG genre is host to some of the longest games available. However, Paper Mario: The Thousand-Year Door is more of an RPG-lite, stripping out a lot of complexities and replacing them with simple action-based mechanics to keep it interesting. So, how long does it take to beat?
This all depends on how much side content you’re going to do and how much you’ll devote to exploration, but on average, it’s about 40 hours in length.
In my own personal experience, that’s about the runtime. I didn’t do absolutely every last activity, but I did take on a great deal of side content, and that’s what I wound up with.
While Paper Mario: TTYD is structurally linear, there’s a decent amount of exploration piled in there. On top of that, you might try finding all the tattle log entries, Star Pieces, or Shine Sprites. Or maybe you’ll battle down the Pit of 100 Trials to gain every last badge you can from the game. There’s a lot that can keep you occupied, even before you reach the credits.
On top of that, the Switch version of Paper Mario: TTYD piles on some additional content to the GameCube version to keep you satisfied for longer.
If you only concentrate on the critical path (only the necessary parts), it could take you more like 32 hours. However, that sounds like a pretty boring way to play. It’s more likely that, even without trying to complete absolutely everything, you’ll hit closer to 40 hours.