Spread fries in an even layer in the air fryer basket. Try to get them as spaced out as possible without touching (even though some touching is inevitable).
Air fry for 12-15 minutes. Start with 12 minutes and check the fries. If they are not to the desired crispiness, put them back in for another 2-3 minutes. (See Note 2.)
Pour the fries onto a serving plate, and serve hot!
Notes
Make sure the fries are taken directly from the freezer. You want them as cold as possible when they go into the hot air fryer for maximum crispiness.
The cooking time of 12 minutes was tested on the 2 qt Philips air fryer and 6 qt Instant Pot Vortex air fryer. If you have a different brand of air fryer, it may require more time. You'll just need to check them after 12 minutes and tack on another 2-3 minutes until they are crispy enough for you.
Avoid using a parchment paper liner, foil or any other liner that could inhibit air circulation and keep the bottom from getting crispy.
You do not need to flip the fries halfway through cooking (even if the air fryer beeps and tells you too, like the Instant Pot Vortex air fryer does).
The longer you cook these fries, the crispier they do get. However, the edges do start to burn, get dark brown, and taste burnt.