In a gallon zip top bag, combine the lemon juice, apple cider vinegar, olive oil, 1 tablespoon parsley, garlic, lemon pepper season, salt, and pepper.
Place the swordfish steaks in the bag, and close the bag. Toss the fish to coat with the marinade, and then place in the refrigerator for about 1 hour, turning every 10-15 minutes.
Once the fish has marinated, preheat the air fryer to 400°F. Set the air fryer to 10 minutes. Lightly oil the inside of the air fryer with a high heat, neutral oil.
Remove the fish from the marinade, reserving the marinade. Place the fish in the air fryer, and top with lemon slices. Close the lid or drawer, depending on the model of air fryer you have, and let cook for 5 minutes.
After five minutes, open the air fryer, push the lemon slices to the side leaving them in the air fryer, and flip the swordfish steaks.
Brush each steak with about a tablespoon of marinade. Close the air fryer to finish cooking the swordfish for the remaining 5 minutes.
Once the fish has reached 145°F, remove it from the air fryer. Serve with browned lemon slices and fresh chopped parsley, if desired.