The Calm Belts are two areas that are just north and south of the Grand Line. These areas almost never have ocean currents or winds blowing, and are also nesting grounds for Sea Kings. They are very effective barriers for those trying to enter the Grand Line. The Straw Hat Pirates encountered the Sea Kings and were caught on top of one of their heads after the crew inadvertently entered one of the Calm Belts. The crew and their ship were sneezed away by a larger Sea King, which implies that the Sea Kings do not stay in the Calm Belts consistently.