The Upper Island refers to the elevated grove found on the northeastern portion of the island of Matumada. The Upper Island can only be accessed by players with traveling-based equipment (jump boost, walkspeed, etc.) to explore the grove and the flat-sided peak on the Upper Island's grounds.
The Upper Island's landscape consists mostly of an 'untouched' grove covered in vines, shrubs, bushes, rocks, and trees scattered across the northeastern portion of the island. The most notable landmark of the Upper Island is the Gargantuan Tree that rests on top of the flat-sided peak, requiring players to somehow climb or fly to the very top of the peak in order to gain access to other collectibles that cannot be accessed by foot. The Gargantuan Tree possesses many solid leaves that players stand on, as well as being home to what may be colonies of mosquitoes buzzing about on certain leaves. Many collectibles and birds can be seen on top of these leaves, as well as possible dangers such as the Maroon Ant and the Cosmic Ghost that can spawn on or near the leaves. Besides that, the Giant Toad's Den can also be found within the grove, however, will require the players to look around the grove's sides to find a partially-blockaded den.
- The Upper Island is the only classified region within the island of Matumada that the game points out.
- Players can utilize various vines within the area to get to higher places, especially at the elevation level where the Gargantuan Tree's leaves may be found at.