i just sailed out of Galveston but we landed at Bush. I bet if the price is right, you could do the same.
I rented a one way car from Budget ( thru Costco) at the airport and returned in Texas City. Rental was $30. From the rental office, we took a cab for $40 flat plus tip to the port. we used Busy Bee taxi. it was an old police car but it served its purpose.
on the return, we took a cab at the port. this was metered and came out to $47.60 back to the Texas City rental office, this time
Avis but same location. this rental was $17!...
we were in and out of the car rental place in 10 minutes each time.
Grand total for my family of 5, including rental, taxi, gas, toll roads, and optional car insurance thru my
travel insurance was less than $250 round trip.
i found this option gave us more flexibility as upon debarkation, we were still able to see a little bit of houston and grab some lunch before heading to the airport for our 4pm flight. we also got to see the space center the day before our cruise.
i also heard that the Avis car rental sometimes shuttles you to galveston for about $50. i cant verify this though.
Shuttles are crazy expensive and it seems like a waste to rent a car just to park it in a garage that yoy also pay for.
Keep chexking the prices thru Costco. when i first booked my rentals, the airpirt pick up price was $50+ but it kept going down.
My return rental however went up to $80 in the weeks after i booked, so my $17 rental was a steal.
we stayed at the Fairfield Inn Texas City which is in the same parking lot as the Budget/ Avis office.