Reaching a depth of 33 meters, Halong Bay’s ocean waters are relatively shallow, making diving and tandem scuba diving immensely popular. Explore over 120 kilometers of coastline filled with reef systems, both tropical and marine flora, colorful fish, rays, and harmless sharks with diving adventures on the stunning Cat Ba Island, Cong Do Island, and Monkey Island. In addition, Trai Cave and Van Gio Island feature ancient submerged limestone formations.