Commercial divers work underwater to build or repair structures. They also perform search and rescue duties.

Commercial divers get written or verbal information about their tasks before entering the water. They also check the environmental conditions of the dive, such as the temperature and clarity of the water. With the help of dive tenders, they put on their gear and get into the water.

For some tasks, divers wear scuba gear. Scuba means Self-Contained Underwater Breathing Apparatus. In this case, divers carry their air supply in tanks on their back. For deeper or longer dives, divers use umbilical systems. During these dives, divers wear helmets and use an air line to the surface.

Some divers construct and maintain underwater structures. They inspect structures for damage and repair them. For this work they use welding equipment, drills, and other tools.

Divers also construct structures underwater. They may remove rocks or other obstacles to make room for the structure or to level the ground. Some items can be removed by cutting them into smaller pieces. Divers sometimes must blow up rocks. They drill holes in the rock, add explosives, and set up other equipment needed to trigger the explosion. Once the area is clear, divers begin building the structure.

Some divers search for missing objects or people. When they find objects, divers attach rigging to them so they can be hauled to the surface. Some divers take photographs of underwater structures or marine life. They may also remove garbage and pollution from the water.

For safety reasons, divers keep track of the length and depth of their dives. They communicate with dive tenders by signal line or dive radio. Divers clean their diving gear after each use. They use brushes, detergents, and other cleaning solutions to remove salt and other contaminants. Divers also keep track of changes in diving gear and underwater tools by reading diving magazines and books.