Preheat your air fryer to 400°F (205ºC) for 3-4 minutes before putting the potatoes in. If you want to flavor them with any extra seasonings, this is the best time to pour them into a bowl and toss them with 1-2 teaspoons of seasonings.
Once it prompts you to add food, pour your frozen roasted potatoes in the air fryer, making sure they're as spaced-apart as possible, pushing them against the sides of the basket if needed. I don't recommend using an air fryer paper liner for this recipe, to allow the most air circulation to crisp up the potatoes.
Most frozen roast potatoes come with oil already on the outside since they're precooked, but if yours don't, then spray them with a tolerated oil spray and cook them for 16-18 minutes (add 2 more minutes for larger frozen potatoes), shaking the basket halfway through.
Check to make sure they're fork tender before pouring the crispy potatoes onto your plate. Then just taste one and season with any extra salt you desire, and they're all ready to enjoy! Serve with your favorite sauce, if unseasoned.