Few studies have described the current clinical practices, adherence to guidelines, and outcomes of newborn resuscitations attended by emergency medical services (EMS). SimBox, a novel, video-augmented simulation, was used to describe the adherence of prehospital providers to Neonatal Resuscitation Program guidelines, to measure satisfaction with the simulation intervention, and to describe the self-reported improvement in knowledge, skills, and attitudes after the simulation. A prospective observational cohort study of EMS providers was designed and conducted using SimBox, an open-access simulation platform, and facilitated by EMS educators. Clinical performance measures were collected using a five-item checklist. Simulation satisfaction measures were collected through net promoter scores. Learners' demographics, and self-reported knowledge, skills, and attitudes were measured using a retrospective survey of 25 questions. In total, 33 facilitator and 55 learner surveys were collected across Connecticut, Colorado, and Alaska between July 2021 and September 2022. At least one deviation from clinical guidelines occurred in 22/30 (73.3%) of the sessions, with 10/30 (33.3%) teams inappropriately performing chest compressions, 5/31 (16.1%) teams not warming, drying, stimulating, and suctioning the newborn, and 7/31 (22.6%) teams not performing positive pressure ventilation correctly. Lastly, 10/30 (33.3%) teams administered an incorrect dose of dextrose-containing fluids. Very high levels of satisfaction were reported with net promoter scores of 97 and 82 out of 100 for the facilitator and learner surveys, respectively. Finally, all 55/55 (100%) of the learners strongly or somewhat agreed that the simulation improved their knowledge, teamwork, communication, and psychomotor skills. In this cohort of prehospital providers, clinical management decisions during a newborn resuscitation simulation often deviated from the gold-standard, newborn resuscitation guidelines. Free, online, open-access simulation resources like SimBox can be used to identify and measure practice deviations from standardized resuscitation protocols in the prehospital setting.