Thoroughly wash and pat dry the fingerling potatoes to ensure maximum crispness.
In a large mixing bowl, combine the halved potatoes with olive oil, salt, pepper, garlic powder, and rosemary.
Toss the potatoes until evenly coated with the oil and spice mixture.
Preheat the air fryer to 400°F (200°C).
Arrange the potatoes in the air fryer basket in a single layer, ensuring they are not overcrowded to allow for proper airflow.
Cook for 15 to 20 minutes, shaking the basket halfway through the cycle to ensure even browning.
Remove once the potatoes are golden brown and fork-tender.
Serve immediately while hot.