How to Reheat Crab Legs? Start by thawing them if they're frozen. Then, steam them for 5-7 minutes or until heated through. Alternatively, wrap them in foil and bake in a preheated oven at 350°F (175°C) for 10-15 minutes. Another option is to place them in a microwave-safe dish, cover them with a damp paper towel, and microwave on high for 2-3 minutes. Enjoy your delicious reheated crab legs!