I'm late to this post, but I know you can take the Paradisus Palma Real boat for a snorkeling trip, i thought it was less than $50 per person, i think it was around $30.
I'm doing welcome bags, delivering them to everyone before we leave for the trip, and having them bring them. this way i don't have to lug more stuff than i'll already have. just an idea. it stinks that we can't ship stuff down because the postal system isn't reliable there.