Lobsters don't stay fresh long after they leave the water; that's why you'll typically find lobsters sold live from saltwater tanks rather than on ice like other seafood. Soft shell lobsters, in particular, are highly perishable. As a result, lobster suppliers often sell pre-cooked and frozen whole lobsters in order to ensure a fresh product with less hassle for shipping and storage. Since frozen lobster already is cooked, you must take care in reheating it so that the meat doesn't become overcooked and tough.
Thaw the frozen lobster in the refrigerator for 24 to 36 hours. You can cook lobsters without thawing, but slowly thawing the lobster gives the meat a better texture.
Check the package to find the weight of the lobster. In a large pot, combine 2 qt. water and 2 tbsp sea salt per each pound of lobster.
Bring the water to a boil and add the lobster. Boil for one to two minutes, long enough to heat the meat without overcooking it.
If you don't want to simply eat the reheated lobster in the shell, you can thaw the frozen whole lobster, remove the shell and heat up the meat in a variety of recipes, such as lobster pasta, lobster pot pie or lobster quesadillas. You can cook your own fresh lobsters and freeze them if you want to enjoy lobster out of season. Simply cool the cooked lobster, wrap it tightly in cling film and place it in a zipper-top freezer bag. Squeeze out as much air as you can before sealing the bag, and then store in the freezer.
If you purchase frozen lobster tails instead of frozen whole lobster, they may be raw. They will need to be cooked longer.