Toss diced potatoes in a large bowl with olive oil, sea salt, and black pepper until evenly coated. Preheat the air fryer at 400 degrees for 3 minutes.
Once the timer goes off, place the potatoes into the air fryer basket. Air fry at 400 degrees for 20-25 minutes, pausing to shake the basket half-way through Once are crispy on the outside and tender on the inside (time potatoes will depend on type of air fryer, 25 minutes is the perfect time for my Ninja air fryer), transfer potatoes to a serving tray or bowl and toss with the pesto.