First things, First: Always thaw lobster tails if they are frozen. Tails must never be cooked from the frozen state.
The most effective way to do this is by placing them in the refrigerator for 24 hours prior to cooking. If you need them faster, you can thaw at room temp for a few hours, and if you need them right away thaw under running cold water.
Get Maine Lobster recommends planning to receive your lobster tail order a day or more in advance of the date you intend to prepare them. Weekday deliveries are recommended for frozen lobster tail orders.