Slice the peeled sweet potatoes into 1/4-inch thick even slices using a sharp knife or mandoline slicer.
Preheat the air fryer to 130°F (54°C) or the lowest setting available.
Arrange the sweet potato slices in a single layer in the air fryer basket, making sure they do not overlap.
Air fry the sweet potato slices at 130°F (54°C) for 1 hour.
After 1 hour, flip each sweet potato slice over to ensure even drying.
Continue air frying at 130°F (54°C) for an additional 1 hour or until the slices are dry and chewy but not brittle.
Remove the dried sweet potato slices from the air fryer and let them cool completely before serving to your dog.
Store the treats in an airtight container at room temperature.