Lifeguard sign and safety flag at Assateague Island National Seashore Jeff Clark, NPS. Always wear a life jacket when you are on, in or near the water. Wearing a life jacket can save your life! Karlie Roland, NPS. Swim in designated lifeguard areas - Some national parks have designated swimming areas where lifeguards are on duty. Some estimates indicate that the chance of drowning at a beach protected by lifeguards can be less than one in 18 million. Consider choosing to swim in a lifeguarded area if available. Be sure to check the days and times lifeguards are on duty at the park and follow all signs.