Background In patients with coronavirus disease (COVID‐19) due to severe acute respiratory syndrome coronavirus 2 infection, pneumomediastinum has been increasingly reported in cases of noninvasive oxygen therapy, including high‐flow nasal cannula, and invasive mechanical ventilation. However, its pathogenesis is still not understood. Case Presentation We report two cases of pneumomediastinum in acute respiratory distress syndrome (ARDS) caused by COVID‐19. In both cases, control of spontaneous breathing with neuromuscular blocking agents resulted in resolution of pneumoperitoneum. Conclusion The improvement of pneumomediastinum with control of spontaneous breathing suggested patient self‐inflicted lung injury as a possible mechanism in this case series. In ARDS cases with pneumomediastinum, in addition to controlling plateau pressure with conventional lung protective ventilation, spontaneous breathing should be controlled if the patient’s inspiratory effort is suspected to be strong.