Hi nic - if you book a trip with the reps then you will have to pay the asking price, whether you participate or not. Hubby & I did the trip over to Cozumel, to swim in the sea with the dolphins quite a few years ago now, so I cannot help with prices, but I know there were people there that were just spectators. Is the trip over to Cozume? If so, there is a public ferry operating, which the other 2 could catch, & then get a taxi on the other side.