In order to cross rivers and access other parts of your deserted island, you'll need to unlock the Vaulting Pole in Animal Crossing: New Horizons.
How to Get the Vaulting Pole
As with all tools available in the game, you will need to craft the Vaulting Pole yourself. To do this, you will need a DIY Recipe.
Here are the steps to follow:
- After giving Tom Nook several fish and insects at Resident Services, he'll call his friend Blathers to come and settle on the island.
- Blathers is the curator of the Museum. After setting up his tent on the island, he will give you two very useful recipes: the Shovel to dig up Fossils, and the Vaulting Pole to access other parts of the island.
How to Craft the Jumping Pole
Once you have the recipe, go to Resident Services and use Tom Nook's workbench to make your Pole.
To use the Pole, select it in your inventory, go to a river and press the A button.