DivingPrincessE
Contributor
The only catch is, if you booked your dive through the cruise ship, you would know that they will HOLD THE SHIP for you if you returned late.
My mom and I are pretty avid cruisers and they will not hold the ship for you, even if you are with their excursion. All they do is pay to fly you to the next island...and if you have just been diving you aren't going to be able to fly for 12-18 hours. If you have good travel insurance with trip interruption and other options, you get flown to the next island for no cost anyway. I wouldn't book a dive at an island unless we were going to be there all day anway. All of the dive trips I have planned for my next cruise pick me up at the pier, 15-30 minutes after we dock. The dive trip is planned for four hours...but even if things go wrong I doubt it will take 8 hours.
Even though they won't hold the ship for you until you get back, they do delay it. There was a couple that was left at Cozumel on our last cruise and the ship left about 45 minutes late. About 20 minutes after we had left we saw a smaller motor boat leave the ship and it returned shortly with the people we left behind.
The only time a ship might wait for people on an excursion is a large percentage of passengers are on that excursion, like was the case for the zipline/cave tubing in Belize. I'm not saying they returned late (they didn't), but it seems like hundreds of people did that (about 3/4 of the auditorium) and I doubt they would leave that many people behind. They might hold the boat for the 15 or so divers, but I wouldn't want to be one of the 2 or 3 on the deep sea fishing exursion if there were delays.