Preheat air fryer to 390°F (200°C) for 5 minutes. This helps the salmon cook evenly and get crispy.
Take frozen salmon fillets straight from the freezer, no need for thawing.
Using a paper towel, pat off any ice crystals on top of the fillets.
Place frozen salmon in the air fryer basket and cook for 5 minutes. If with skin, place skin-side down in the basket.
In a small bowl, whisk together olive oil, lemon juice, salt and pepper to taste.
Open the air fryer and lightly brush the fish with olive oil marinade.
Cook for 7 to 10 minutes, depending of the thickness of your fillets. Do not overcook to prevent drying.Frozen salmon is ready when it reaches an inside temperature of 145°F (62°C), if measured with a food thermometer. It should be golden outside and flaky inside.