The ladder is a tool in Animal Crossing: New Horizons that enables the player to access higher and lower levels of islands. The tool is introduced during the villager house development quest, in where Tom Nook will send the player the ladder recipe after the second plot is placed so that the player can gather the flowers that are available on higher tiers of the island.
Any players other than the Resident Representative must either have the item crafted by another player, or else purchase the recipe from Nook's Cranny once it opens.
While holding the ladder the player faces a ledge that is either higher or lower than the player. When used, the player animates extending the ladder and then either climbs up or down to the destination. The destination cannot be water or an area that is blocked by a tree, rock, water or other feature where the player could not normally walk. It is possible to use the ladder on a diagonal cliff.
The ladder will not break after any number of uses. It shares this infinite durability property with the vaulting pole.
The ladder cannot be used on a fourth tier of the cliff either from being created with the use of Island Designer app or on the fin island from the Mystery Island Tour. Attempting to climb on said cliff will give the player a message: "It's too dangerous to climb any higher."
DIY recipe screenshot