Glossopharyngeal breathing, frequently performed by elite breath-hold divers, relies on muscles of the mouth and pharynx to move air into (glossopharyngeal insufflation, GI) and out of the lungs (glossopharyngeal exsufflation, GE). GI has also been used by patients with weak respiratory muscles. Fluoroscopic and endoscopic examinations were performed on four divers (three of whom were world record holders) during both GI and GE maneuvers. A detailed pictorial description of both GI and GE, with online video material that includes external, endoscopic and fluoroscopic examinations, is provided in this publication. Both GI and GE are accomplished with a coordinated series of contractions by glossopharyngeal muscles and they rely on a piston pump-like action of the larynx. In particular, the larynx moves extensively and repeatedly up and down, to either inject air into (GI) or extract it from the lungs (GE), with the vocal cords functioning as a valve. During both maneuvers, when the larynx is in its highest position, the epiglottis does not fold back, unlike what happens during swallowing.