Respiratory complaints like swimming induced pulmonary edema (SIPE) are a common feature of United States Navy Special Warfare (NSW) training. We designed a study to evaluate the incidence and clinical features of SIPE seen in this population.We designed a prospective, observational review of all NSW candidates over a 15 month period. We obtained baseline height, weight, and an electrocardiogram (EKG). Candidates with respiratory issues were evaluated with a two-view chest radiograph (CXR) and EKG while symptomatic and were closely followed up. The CXR and clinical data were then independently reviewed.2117 NSW candidates participated in training during the study period, with 106 cases of SIPE identified (5.0%). 10 further cases of SIPE were repeat episodes in candidates already diagnosed. 44 cases of pneumonia were identified (no repeat cases). The majority had: cough (90.4%), frothy-pink sputum (35.6%), and hemoptysis (23.7%). 80.1% of candidates had an oxygen saturation ≥90%. Physical exam findings were variable: crackles (50%), wheezing (36%), and rhonchi (19%). Several had more than one feature. 23% presented with a normal exam. Radiological findings in SIPE patients showed most commonly an interstitial pattern with perifissural thickening, larger average azygos vein diameter, larger average heart size, and normal lung height. EKG findings were not significantly different than baseline. Height and weight were not significantly different between the groups. Lower water temperatures were suggestive of increased SIPE incidence, but this was not a statistically significant trend.The burden of SIPE in NSW training was greater than anticipated. Clinical symptoms and physical exam assisted by imaging were able to differentiate SIPE from pneumonia. EKG was not a useful diagnostic or screening tool. Height and weight did not affect risk of SIPE. IRB registration at Naval Medical Center, San Diego. Registration number: NMCSD.2017.0020.