There is a masters certification from ASCA. It involves some take home courses and other requirements. To become level 1 certified the requirement is basically a degree, the certification and a few months of coaching. You can make up for the lack of a degree with more experience.

ASCA will get you certified to coach but that doesn’t mean you will become a coach. To become a coach you need to find a place to coach.

To do that the easiest way is to start your own program. Find a local pool without a masters program, talk to the manager and tell them you have taken your certifications but need experience. Then offer to coach a new masters session for free. Or offer to share the fees collected. Since you’re brand new a month of free workouts followed by charging $2 or $3 per workout after that can be a good way to get off the ground. After that, you can usually swing a free pool membership in exchange for coaching.

This might be best accomplished in the summer when neighborhood pools open.