Scrub thoroughly the potatoes under cold running water. Once clean, pat them completely dry with a clean kitchen towel. The skin needs to be dry to crisp up in the air fryer.
Prick the potatoes all over using a fork to allows the steam to escape while cooking. Coat each potato with olive oil. Sprinkle the sea salt uniformly over the potatoes. This helps both the flavor and get a crispy skin.
Place the potatoes in the air fryer basket. Make sure to leave some space between to allow the air to circulate. Set the air fryer to 400°F and cook for 30 minutes.
Flip the potatoes using tongs. Continue to cook for an additional 5 to 15 minutes. The potatoes are done when a fork can easily slide into the center. The exact time will depend on the size of your potatoes.