From Sugar Land or Missouri City, budget 75 to 90 minutes down Beltway 8 to I-45 South and over the causeway. From Katy or Cinco Ranch, plan on about an hour and a half, and from Richmond and Fulshear the longer end of that. The Port of Galveston's own arrival guide puts Hobby (HOU) at roughly 45 minutes and George Bush Intercontinental (IAH) at about an hour and a half.
Everyone from the north or west takes the same road: I-45 South onto Galveston Island, then Harborside Drive to the port. That is the pinch point. On a Sunday with several ships turning around, the last few miles take far longer than the map says, so treat those numbers as free-flow and add to them.
