Pulmonary function was measured in 48 air divers (age range: 8–38 yr) and 56 control participants (age range: 8–34 yr). Static lung volumes, dynamic lung volumes and flows, and the pulmonary diffusing capacity for carbon monoxide were measured twice, 29 months apart. At both times the adult divers (>18 yr) had higher forced vital capacity, forced expiratory volume in 1 s and maximal expiratory flow rate at 50%, as well as lower pulmonary diffusing capacity for carbon monoxide, than did the adult controls. Whatever the age, mean annual changes in these parameters did not differ between groups. Our results indicate that there were no significant changes in pulmonary function in the young (8–12 yr), adolescent, or adult divers compared with healthy controls over the 29-month period. The mean annual changes in forced expiratory flow and volume, however, were negatively correlated with number of years of diving experience in adult divers and with maximal diving depth in adolescent (13–18 yr) divers (p < .05 and p < .001, respectively). Deep diving during the teenage years coupled with years of recreational diving might increase the risk of airway obstruction.