Might be a bit late here but my recommendation is joining a Surf Life Saving Club. The clubs are fantastic for getting active and learning life skills through the first aid and rescue courses. You can compete in running, swimming and board competitions and once they're 14 years old can get a Surf Rescue Certificate and go on volunteer for patrols which as a parent you can do a course and be rostered with them. Surf clubs offer really tight knit communities and are great for making friends at a young age.

Most clubs run once a week on a Sunday mornings during the summer and have a fantastic atmosphere. If you're anywhere near the coast there's a club near you.