Like sailing, scuba diving is a sport and a recreational pastime enjoyed by millions of Americans, and like sailing, thousands more people are taking scuba-diving lessons each year, so they too can enjoy recreational scuba diving. The number one requirement for starting a scuba diving instruction business is, of course, to be a certified scuba diving instructor. There are many training facilities in the United States. However, the best and most recognized scuba diving instructors' program is one that is provided by PADI (Professional Association of Dive Instructors). The course will take a few months to complete and will cost a few thousand dollars. Once certified, scuba diving instruction classes can be marketed directly to potential students via all traditional advertising and marketing mediums. Or, the business can be partnered with an existing scuba diving retailer or charter boat operation. The bottom line is that you can have a lot of fun, make a decent income and really enjoy your work.