My question is. If you go out on an American ship and come back on same ship [so exactly same people on board] why do you do immigration at all on the ship? In England the ship checks your passport at the start and customs [in the customs hall not on ship] check it at the end. No getting up at 5am and forming queues around the ship. I'm not being tetchy just confused by the process.
Me replying to my own post! I just remembered that when we cruised on Grand Princess in the Med [out of Barcelona] we didn't do that immigraton thing at all [well we did it but in the customs hall and no eraly getting up] it was only with NCL in the Caribbean. Why is this guys, any ideas?
There's a US maritime law called the Passenger Services Act (also known as the Jones Act) that requires all foreign-flagged passenger vessels to include at least one foreign port in their itinerary when sailing to and from an American port. So all Caribbean cruise ships - in fact, all cruises beginning and ending in the US - must pass through immigration and customs checks at the end of their voyage.
In order to meet the requirements of the PSA, it is sometimes necessary for ships to make a big detour to include a foreign port. Ships sailing to Alaska and back have to stop in Canada. Ships sailing along the Pacific coast have to stop in Mexico. Seems silly, but it's a law imposed by the lobbying of various US maritime unions.
Remember that all cruise ships presently in service are NOT US flagged ships, and are not "US ships", even though the line has its main office in the US. NCL will soon begin cruising Hawaii - only cruises with US flagged ships and US crew under an exception to the Jones Act granted to them --- which was required because the ships were not US built as also required by the Jones Act. Perhaps customs and immigration checks won't be required for these, but only time will tell.