Preheat your air fryer to 400°F. Wash and dry the sweet potatoes thoroughly, then use a fork to poke holes all over each potato.
Rub each sweet potato with olive oil and sprinkle with salt evenly. Place the potatoes in the air fryer basket in a single layer.
Cook at 400°F for 35-45 minutes, turning them halfway through to help them cook evenly. Check for tenderness with a fork. Cooking time will vary depending on the exact size of the sweet potatoes.
Remove the sweet potatoes from the air fryer and let them cool for a few minutes. Slice them open and fluff the insides with a fork. Serve with butter or any extra toppings you enjoy.