presuming you're cruising out of galveston, i have never been there so don't know how their port procedures work. that said, royal doesn't generally have port arrival times like disney does, except on their quantum-class ships which have a different check-in procedure. so, i'm 99% sure you can just show up whenever. boarding in nj and fl usually starts around 11-ish; we try to get to port around 10:30. paperwork will usually have a later boarding time, and sometimes royal sends emails or robocalls telling you to come later, but we always arrive early and have never had a problem; the calls/emails are just because they are trying to spread out the crowds. if you plan to come later, obviously just pay attention to all-aboard time, as that is set in stone.