Background: Congenital diaphragmatic hernia (CDH) is a rare congenital anomaly with abnormal diaphragm development, typically diagnosed prenatally or soon after birth. Late-presenting CDH presents diagnostic challenges due to nonspecific symptoms that can lead to misdiagnoses. Methods: This report discusses a 35-month-old female initially presenting with predominant gastrointestinal symptoms and minimal respiratory distress. Initial radiographic findings suggested a left tension pneumothorax, prompting further investigation. Results: Subsequent diagnostic efforts revealed a Bochdalek-type left CDH, with several abdominal organs herniated into the thoracic cavity. The case was managed through laparotomy, where herniated contents were successfully repositioned into the abdominal cavity. This intervention underscores the need for high clinical suspicion and the importance of distinguishing between similar presentations, such as tension pneumothorax and tension gastrothorax, which require different management strategies. Conclusion: The case illustrates the importance of considering CDH in differential diagnoses for older pediatric patients with atypical symptoms. Early recognition and appropriate management are key to improving patient outcomes.