Cut each marshmallow in half. Break each graham cracker in half. Break each chocolate bar into 4 pieces.
Place both halves of one marshmallow, sticky side down, on to the inside of one graham cracker piece. Press down to adhere.
Place the marshmallow-topped graham crackers into the air fryer basket in a single layer.
Air fry for about 3 minutes, until marshmallows are slightly browned. You may have to place any errant marshmallows that may have fallen off back onto the graham crackers.
Quickly remove from the air fryer, place 2 pieces of chocolate on top of the marshmallow and top with another piece of graham cracker.
Allow the heat from the marshmallows to melt the chocolate for a few minutes before enjoying.