Prepare the Apples: Wash the apples thoroughly. Peel them if preferred, or leave the skin on for extra texture and fiber.Core and slice the apples into even slices, about 1/8 to 1/4 inch thick.
Soak the Apples (Optional): To prevent browning, mix water and lemon juice in a bowl. Soak the apple slices for 5-10 minutes and pat them dry with a paper towel.
Preheat the Air Fryer: Set your air fryer to 130°F to 135°F (54°C to 57°C).
Arrange the Apple Slices: Lay the apple slices in a single layer in the air fryer basket. Ensure they aren't overlapping to allow proper airflow for even dehydration.
Dehydrate the Apples: Set the air fryer for 3-6 hours, depending on the thickness of the slices and your desired crispiness. Check every hour or so for doneness.
Cool and Store: Once the apples are dehydrated and crispy, remove them from the air fryer and let them cool completely. Store the cooled dehydrated apples in an airtight container or vacuum-sealed bag.