Podoplanin (PDPN)/T1 alpha is known as a specific marker of lymphatic endothelial cells and type I alveolar cells. Sensitive and specific monoclonal antibodies (mAbs) for PDPN are needed for immunohistochemical analyses. Recently, we developed an anticetacean PDPN mAb, PMab-237. Herein, immunohistochemical analyses showed that PMab-237 strongly detected pulmonary type I alveolar cells, renal podocytes, and lymphatic endothelial cells of the harbor porpoise. These findings suggest that PMab-237 may be useful for immunohistochemical analyses for cetacean tissues.