No, cruise ships do not dock on the island, they dock in Belize City and some of the cruise people take the ferry to the island. "Cruise days" are days that the ships come to Belize City and the cruisers take the day tours to AlTunHa,Maruba, Lamamai, snorkel and dive. So these places are like extra crowded.
Someone correct me if I am wrong somewhere!!!
Jackie