Wash and dry the sweet potatoes
Pierce each sweet potato several times with a fork
Lightly coat with oil if desired
Sprinkle with salt if desired
Preheat the air fryer to 375°F
Place the sweet potatoes in the air fryer basket
Cook for 35 to 45 minutes, depending on size
Flip halfway through cooking
Check for doneness by inserting a fork or knife
Cook longer if needed until tender
Remove from the air fryer and let cool slightly
Slice open and serve