As counterintuitive as it seems, frozen shrimp is among the freshest you can buy. Most shrimp is frozen right after it's caught, directly on the boat. Thawing frozen shrimp may seem like an extra step when you can buy it ready-to-eat from the grocery store fish counter. That ready-to-eat shrimp is usually just frozen shrimp that's been thawed by the store staff. Since shrimp's eating quality and food safety status deteriorate quickly, you're better off being in control of the thawing process. Thawed shrimp works well with cocktail sauce, in seafood recipes or as a salad topping.
If you know you want shrimp tomorrow, place it -- package and all -- in the refrigerator. Thawing shrimp in a 40-degrees-Fahrenheit -- or-below -- environment keeps it safe from pathogens.
Place the shrimp, sealed in packaging or placed in a zip-top plastic bag, in a bowl of cold water. If you can, arrange the bowl in your sink so that the faucet drips a regular trickle into the bowl as the overflow pours down the drain. This method takes about 15 minutes, depending on the size of the shrimp.
Save the microwave defrost setting for shrimp you plan to cook shortly after thawing. Use your machine's defrost cycle and only thaw until the shrimp is bendable -- but still quite cold and icy.
These methods work for shelled, tail on or peeled frozen shrimp.