A good cooking time for crab legs depends on how they will be prepared. If boiling or steaming the crab legs, 4 to 6 minutes is usually enough. If baking the crab legs in the oven, they will take closer to 15 minutes.
To bake crab legs in the oven first they must be thawed. The safest way to thaw frozen fish is to leave them wrapped in the refrigerator for about 8 hours. Once thawed, season the crab legs to taste then wrap them in aluminum foil, leaving enough space to tent over the crab. Place in the oven at 375 F for 15 minutes.