Spontaneous pneumomediastinum (SPM), unrelated to mechanical ventilation, has been newly described as a complication of patients with coronavirus disease (COVID-19) pneumonia without the associated risk factors. The main objective of presenting this case is to highlight a rare but important complication among patients with COVID-19 pneumonia treated only with a high-flow nasal cannula (HFNC). We aim to study the possible underlying pathophysiology of this phenomenon.