Keep shrimp cold at all times during preparation. You can freeze shrimp with shells on (better protection, longer storage life) or peeled and deveined (more convenient to cook). If freezing shell-on, remove the heads if still attached.
Brine-freeze method (best for home): Place shrimp in rigid containers. Cover completely with a solution of 2 tablespoons salt per quart of water. Leave ½ inch headspace. The brine creates a solid block of ice around the shrimp, providing excellent protection from air. This is the closest a home cook can get to commercial frozen shrimp quality.
Flash freeze and bag: Spread individual shrimp on a parchment-lined sheet pan in a single layer. Freeze until solid. Transfer to freezer bags, press out air, and seal. Shrimp frozen this way can be pulled out individually.
Vacuum seal: Arrange shrimp in a single layer inside vacuum bags. Seal. Excellent results with minimal effort.
3 to 6 months (shell-on). 3 to 4 months (peeled).
The fastest safe method: place shrimp in a colander under cold running water for 5 to 10 minutes. For the brine-freeze method, thaw the block in a bowl of cold water. Shrimp can also be cooked from frozen — add 1 to 2 extra minutes of cooking time.