Traumatic injuries are a leading cause of morbidity and mortality, particularly among young adults. Direct transport to the operating room has been associated with reduced mortality by minimizing treatment delays. The extended Focused Assessment with Sonography for Trauma (eFAST) is a critical diagnostic tool in trauma care, identifying life-threatening conditions that may require urgent surgical intervention. This study aims to assess the diagnostic accuracy of eFAST performed by paramedics in a prehospital environment, comparing their interpretations to those of expert physicians. A retrospective observational cohort analysis was conducted on trauma cases (n = 64) attended by South Metro Fire Rescue from January to December 2022. Paramedics underwent comprehensive training in ultrasound use and interpretation before performing eFAST exams in transit to medical facilities. Exam findings were compared to interpretations by an expert ultrasonographer, with sensitivity, specificity, and predictive values calculated. The cohort consisted primarily of males (63%), with a mean age of 46 years. The most common injury mechanism was motor vehicle crash (n = 20). Paramedic-conducted eFAST exams demonstrated a sensitivity of 80.0% and specificity of 95.8%. Positive and negative predictive values were 50% and 95.8%, respectively. False positives were largely due to difficulty in interpreting normal anatomy or identifying pathologies. Paramedics can reliably perform eFAST exams with high diagnostic accuracy, suggesting that prehospital eFAST could enhance trauma care by reducing time to surgical intervention. Future research should explore the integration of eFAST into prehospital protocols across diverse settings to improve trauma outcomes.