It takes four to five minutes to boil snow-crab legs. To boil snow crabs, fill a large pot two-thirds full of water, and add 1 tablespoon salt to the water. Bring the water to a boil, and submerge the snow-crab legs into the water.
Boil the snow crabs uncovered for the recommended time, tucking and bending the legs as necessary to ensure they remain submerged in the water throughout the boiling process.
Snow-crab legs are usually precooked by the seafood manufacturing company that distributes the seafood to retail stores. The boiling water permeates the shells of the snow-crab legs, which helps keep the meat moist as it heats up.