Pour the water into the Instant Pot and place the metal trivet or a steamer basket inside. Arrange the frozen lobster tails on the trivet or in the basket, ensuring they don’t overlap.

Secure the lid and set the vent to "sealing." Set the Instant Pot to "Manual" or "Pressure Cook" mode on high for 2 minutes (for smaller tails, 4-6 oz) or 3 minutes (for larger tails).

Once the cooking cycle completes, turn the vent to "venting" for a quick release. After pressure releases and the float valve drops, open the lid and remove the lobster tails with tongs.

Once cooled enough, using kitchen shears, cut down the center of the hard top shell of the lobster tail, stopping at the base of the tail. Gently pry the shell apart without completely breaking it off. Run your finger between the meat and the shell to loosen it and remove any visible veins.

Prepare a sauce by mixing melted butter, minced garlic, lemon juice, salt, and pepper. Drizzle the sauce over the tails, garnish with parsley and lemon slices, and serve immediately. Enjoy!