As an introduction to three of the lagoon islands, this is a very good trip which offers value for money - under £18 each on trip advisor. It lasted from noon to 4.30pm, departing and arriving back from San Marco. Book on trip advisor, take your email to the booth by the boats and exchange for a ticket. You get about 45 minutes on each island, long enough for coffees or snacks. There is some commentary on the boat but it is fairly simple stuff. Overall, a good day out.