In this case study, we evaluate the unique physiological profiles of two world-champion breath-hold divers. At close-to current world record depths, the extreme physiological responses to both exercise and asphyxia during progressive elevations in hydrostatic pressure are profound. As such, these professional athletes must be highly capable of managing such stress, to maintain performing at the forefront human capacity. In both divers, pulmonary function before and after deep dives to 102 and 117 meters in the open sea were assessed using non-invasive pulmonary gas exchange (indexed via the O2 deficit, which is analogous to the traditional alveolar to arterial oxygen difference), ultrasound B-line scores, airway resistance and airway reactance. Hydrostatic-induced lung compression was also quantified via spirometry. Both divers successfully performed their dives. Pulmonary gas exchange efficiency was impaired in both divers at 10 min, but had mostly restored within a few hours. Mild hemoptysis was transiently evident immediately following the 117m dive, whereas both divers experienced nitrogen narcosis. Although B-lines were only elevated in one diver post-dive, reductions in airway resistance and reactance occurred in both divers, suggesting the compressive strain on the structural characteristics of the airways can persist for up to 3.5hrs. Marked echocardiographic dyssynchrony was evident in one diver after 10m of descent, which persisted until resolving at ~77m during ascent. In summary, despite the enormous hydrostatic and physiological stress to diving beyond 100m on a single breath, these data provide valuable insight into the extraordinary capacity of those at the pinnacle of apneic performance.