Heat an air fryer to 350 to 360°F.
Pierce the casings of 4 uncooked bratwurst sausages in several spots with a fork or a thin knife.
Place the sausages in the basket of the air fryer in a single layer. Air fry until the skin is crisp and an instant-read thermometer inserted into the center of the sausages registers at least 160°F, 10 to 12 minutes.