A wearable radon detector is an apparatus that measures radon exposure around a user. The apparatus includes a housing, an elongated plate, and a radon-detecting foil strip. The housing contains the elongated plate and the radon-detecting foil strip. The elongated plate positions and maneuvers the radon-detecting foil strip. The housing includes a receptacle portion, a storage portion, a first breakaway line, a plate-receiving slot, and a plurality of air passages. The elongated plate includes a grasping member, a setting member, and a second breakaway line. Radon collects within the receptacle portion through the plurality of air passages. The storage portion shields the radon-detecting foil strip once setting member has been slid from the receptacle portion and into the storage portion, the receptacle portion has been separated from storage portion along the first breakaway line, and the grasping member has been separated from the setting member along the second breakaway line.