Preheat the air fryer to 375°F (190°C) for 3–5 minutes.
In a mixing bowl, toss the potato pieces with olive oil, salt, pepper, and rosemary (and any optional seasonings).
Place the potatoes in the air fryer basket in a single layer; avoid overcrowding.
Cook for 15–20 minutes, shaking or turning the potatoes halfway through for even crisping.
Check for doneness;potatoes should be golden and crisp outside, tender inside.
Remove from the air fryer and optionally sprinkle with fresh rosemary or a squeeze of lemon juice before serving.