Getting back on the cruise ship on a tendered operation is generally not a problem, as long as you can get back to the tender dock on time to meet the ship's last tender back to the ship. Getting off the ship on a tender operation in a timely manner can be a big problem, if for example your cruise ship is scheduled to dock at 0800 and your independent dive op's boat leaves at 0830. First, the cruise ship gives priorty tendering to their own excursions and their frequent cruisers. Second, sometimes there are tender delays due to getting the tender boats set up, customs issues, or ship crew screw ups. For these reasons, and the fact that the ship's dive ops are very good in GC and Belize, I use the ship's dive excursions at those locations. If docked, and using an independent op, try to be first in line to get off the ship which means you have to go down to the disembarkation door early and wait for the ship to be cleared by customs to start the process. When you choose your cruise line and cruise, call the customer support line and try to find out what is the usual timing for getting off the ship at your various ports. For example, on some cruises, the ship's arrival time is the time they expect to pull up to the dock, with disembarkation time being 25-45 minutes later, and on other cruises, we actually disembarked the ship at or before the scheduled arrival time. Those issues can make a big difference when trying to connect to a dive op that leaves in close proximity to your ship's arrival time. If you book an independent dive op, another big gottcha can be the fact that some (NOT ALL) cruise ships stay on ship's time which is based on the home port time, and is not reset for local time at your ports. More than a few passengers have been left at the dock because the ship's time was not the same as the local time at the port, and the independent local dive ops/excursion vendors use local times. This time difference issue almost bit me in the butt at Roatan several years ago. If you use an independent dive op, make sure you are all on the same page as to when you will arrive and when you need to be back on board. Many on this board are not happy using ship's dive ops because they cost a little more (not always though), are not 6 pack dive boats, and want to dive they way they want to dive instead of diving with a group. The other side of that coin is whether you want to deal with the additional stress of worrying about getting to the dive op in time or losing your pre-paid dive expenses, getting back to the ship on time, and what it is going to cost you to fly your group to the next destination if the ship leaves without you. Final thought, if you decide to use an independent dive op, and the time in port is a little tight, take your passport with you.