The internal temperature of fully cooked shrimp is 120 degrees F, but usually it's easier to go by color instead of temperature since shrimp is little. The color should be opaque white with some pink and bright red accents when it's cooked. A tightly curled tail is also a sign it is cooked through because when shrimp cooks the muscle contracts so the shrimp shrinks and curls. You want it to have a c-shape when it's done.