These are extra-jumbo farm-raised white shrimp sold by the pound from the Costco fresh seafood counter. "U-12" is a sizing designation meaning fewer than 12 shrimp per pound, placing them in the extra-large to colossal category — among the largest shrimp available at retail. They are sold previously frozen and thawed for convenience directly from the display case.

Farm-raised white shrimp (Litopenaeus vannamei) are the most widely produced shrimp species in the world, prized for their mild, sweet flavor and firm texture. At this large size they are ideal for grilling, broiling, sautéing, or serving as a centerpiece shrimp cocktail presentation. Their size makes them forgiving to cook and impressive to serve.

Because they are sold previously frozen and thawed, it is best to use them within one to two days of purchase. They should not be refrozen once thawed. When selecting, look for shrimp that smell fresh and ocean-clean with no off odors and shells that are intact and translucent. They are typically sold head-off and shell-on or easy-peel. Costco sources farm-raised shrimp from countries including India, Thailand, and Ecuador, where aquaculture operations produce shrimp under regulated conditions.