Snorkeling tour for older couple?

My (71m) wife (65f) are going to be on Okinawa in mid May. We are experienced snorkelers and want to go on a day tour. However, we are learning that most tour outfitters have either a 65 or 70 year old age limit. Do you know of good options? We are planning one self guided snorkeling day via the ferry but also are looking for a tour.

Suggestions? Thanks!

by AceArtBox