Lifeguards and lifeguard instructors.
Begin by taking this online training.
When the online portion has been completed, the student prints or emails me the certificate of completion. I then schedule the practical and pool portion of the course.
They qualify with this swim test:
300 yards front crawl or breast stroke
2 minutes legs only water tread with head and hands out of the water
Retrieve a 10lb brick in less than 1:40 – swim out 20 yards, dive down, swim with the brick out of the water on your back to the starting point
Complete the skills in this pdf
Here is the Lifeguard manual.
You will be certified as a LG for two years. I prefer to do a combined course to produce LG instructors following your LG class. The price for aquatic courses for BSA members will be 50% of what the least expensive course in the area is. This should put the LG course at $100. You will also have to pay the $5 to register with this site.
Scuba classes, sailing, and other classes will be priced in the same for BSA members, 50% of the least expensive course in the area and divemasters, sailing and other leaders paid a portion of the course to raise money for their units.
Scuba – here is the instructor manual