We're sailing out of Galveston on the Wonder this winter. Definitely only a shuttle from IAH. It's so pricey anyway, that it's cheaper for us to rent a car than it would be to take the shuttle. If I'm remembering correctly, the shuttle only makes sense if you are cruising single or as a couple, and you're good with the hotel right next to the airport (has a free tram or something to it). Otherwise you have to taxi back to the airport for the shuttle anyway, adding even more to your cost, on top of the high shuttle cost. We're flying in the day before, so it makes much more sense for us to stay in Galveston and rent a car. It seems pretty ridiculous that paying for an 8 day car rental (which isn't getting used most of the time) is a better financial decision than the shuttle, but it is what it is! FYI - car rental rates were slightly cheaper from Hobby, if you are going back and forth between the two airports. It's also closer to the port.