Prepare the sweet potatoes by washing them thoroughly under cold water and patting them completely dry with a clean kitchen towel. Any residual moisture will prevent the skin from crisping properly.
Pierce each potato 5-6 times with a fork or sharp knife to create steam vents, preventing them from bursting during cooking.
Brush each potato lightly but thoroughly with olive oil, ensuring the entire surface is coated. This helps the skin crisp and adds flavor.
Season the outside of each potato with kosher salt and pepper (if using), gently pressing the seasonings onto the oiled surface.
Preheat your air fryer to 390°F (200°C) for about 3 minutes if your model requires preheating.
Place the sweet potatoes in the air fryer basket, ensuring they’re not touching or overcrowded. Leave room for air circulation, cooking in batches if necessary.
Cook for 30-40 minutes, depending on the size of your potatoes. Smaller potatoes may be done in 25-30 minutes, while larger ones might require 40-45 minutes.
Check for doneness at the 30-minute mark by inserting a knife or fork into the center of the largest potato – it should slide in easily with no resistance when fully cooked.
Let the sweet potatoes rest for 5 minutes after removing them from the air fryer. This allows the flesh to become even more tender and makes them easier to handle.
Slice open and fluff the interior with a fork, then add your favorite toppings and serve immediately while still hot.