Preheat the oven on 400 F.
Place the crab legs into a 9x13 bake dish.
Combine the olive oil, garlic, and cajun seasoning in a bowl. Mix until well incorporated.
Divide the oil mixture into two bowls, and set one of the bowls to the side.
Brush the oil mixture on to the crab legs, then cover the bake dish with aluminum foil.
Bake the crab legs in the oven for 10 minutes.
Remove the crab legs from the oven, then brush with more of the oil mixture.
Cover the crab legs with the foil, and bake for an additional 10 minutes.
Remove the crab legs from the oven, then brush with the oil mixture that we set to the side.
Serve and enjoy!