Emergency services were called to reports of two swimmers in distress at Zenith Beach near Shoal Bay on the Central Coast about 2.45pm today.
Friends of the men pulled them from the water before members of the public and local police performed CPR on the pair until paramedics arrived.
One of the men couldn’t be revived and died at the scene.
The second was receiving ongoing treatment at the beach and is in a critical condition.
The two men haven’t been formally identified, but they are believed to be in their 20s.
Zenith Beach, which is located in the popular Tomaree National Park, is not patrolled by surf lifesavers.