Cover the pot and bring to boil. Place your crab legs in basket (You can bend or break the legs to fit into the steamer) and steam for 5 to 7 minutes. The oven is my preferred method for cooking king crab legs. Just place the thawed king crabs single layer in a large baking pan, add about 1/8 inch water to the pan. Cover with aluminum foil and in a preheated 400 degree oven and bake for about 10 to 15 minutes.