Simply Snorkelling.
Snorkelling is for everybody and anybody. If you are not interested in diving it is an alternative way to experience the underwater world, enjoy splashing around and also to keep fit. It can also be a great step towards diving if it seems daunting and intimidating, and can help build your confidence if that's what is needed.
Depending on ability, introductory sessions can start for children as young as 3 and will teach basics in snorkelling equipment and techniques. The sessions range from £15 to £25 depending on numbers, and make a fantastic private or group activity.