Parent-and-Baby swim classes at a rented pool

Parents and grandparents of babies and toddlers, often found through moms' groups, pediatric offices and local community pages.

A fee per course, usually 6 to 10 weekly sessions, paid upfront. Small groups keep the experience good, and extra classes at busy times add income.

• Patient and warm with babies and parents
• Confident swimmer with water safety knowledge
• Clear communication and class planning

• General liability insurance, and check whether the pool owner requires you to be named on your policy
• Check your state and county rules for instructor qualifications and background checks for people working with children
• Water safety: always keep strict parent supervision and small class sizes, and never promise a child will be 'drown-proof'
• Water temperature and hygiene (diaper and swim nappy policies) as babies need warm water, so make sure the pool can provide it

Startup costs are typically around $1,500 to $6,000, depending on equipment, insurance and how much pool time you rent. Check whether the pool owner needs to be named on your insurance policy, as that may affect your costs.

Monthly revenue is typically around $800 to $4,000, depending on class sizes, course prices and how many sessions you run. Treat this as an estimate, and remember that pool rental comes out of what you take in.

Check general liability insurance requirements and whether the pool owner wants to be named on your policy. Also check your state and county rules for instructor qualifications and background checks for people working with children, plus the pool's hygiene and water temperature policies.