IMO the biggest advantage is they're backed by Carnival. If your excursion is late returning, the ship waits. If your excursion is somehow canceled or altered, Carnival credits your sail-n-sign. In ports you are tendered ashore, they will make sure you're placed on the first tenders to make your excursion. Also, they give talks onboard describing the activity level etc for the excursions offered, you've got a better idea what you're buyin. I might consider outside vendors in certain ports, but in others, Carnival's are the only way to go. Yes, they are more expensive.
Yes, I also have to agree about when tours run lake, when booking through the cruiseline, they will wait to leave for you. If you book on your own, you are on your own. Just be careful when booking on your own in each port. Some are very easy to do yourself and if early enough, no worries about being back too late. Same goes for getting in a cab and going to a beach or something, most times you can easily do it and save some money at the same time.
Book at the pier and save big. They will take you to the same places and get you back with time to spare.
You can go back early and skip things you may not like. Fewer people made our excursions one on one with english speaking drivers air conditioned clean cars, vans, buses. Try getting a bus load of strangers to leave early or stop for bathroom breaks and shopping. BOOK at the pier you will be glad you did.
and being shunted in a crowd then book with carnival. otherwise ask on here for advice on booking on the internet beforehand or when you get there. My 2 independent tours didn't charge for the wife who missed the booking due to food poisoning. They didn't start until 9ish so plenty of time to get off the boat at jamaica and grand cayman - cozumel would have been cutting it close due to the long time it took to tender (but then I was in the large boat going to playa del carmen)
The stingray had 8 of us on the boat compared to about a 100 on a cruise booked excursion.
We learned, after our first cruise, that we could get a better value by making our own arrangements.
We do book through the cruise when there is the matter of being tendered. Such as Belize. We didn't want to be tendered into Belize, then find a boat that would take us to Shark/Ray Alley, then have to go back to Belize and get tendered back to the ship. So we just booked through Carnival and the boat picked us up from the ship and went straight to Shark/Ray Alley.
It all depends on your comfort level.
We have "done our own thing" in Ensenada, Acapulco, Manzanillo (one of the best tours we've had!), Zihuatanejo, Progresso, Cancun, Cozumel, San Juan, St. Thomas,and St. Maarten.
We've done ship excursions in Roatan, Belize, Dominican Republic.
you have to give 24 hours notice to cancel a shore excursion with carnival. Any time less than that and they won't give you a refund.... even if the trip was cancelled because you don't meet the health requirements posted under the door of your cabin the night before the trip less than 24 hours before the trip starts. But if you want to go on another excursion instead they will credit you for that one (strangely enough)
its all about your island experience your comfort level and what islands you are going to.
My general rule of thumb is that if i have to travel via water to get to my excursion or i have to travel more than 2 hours by land then i book with the cruise line.
Some excursions you can only get thru the cruise line.
This past cruise was the first time out of 5 Carnival cruise that I booked my own excursions on line. In the past I have always been worried about the ship sailing without me and all the other horror stories of what could happen. If you are going to book your own, check out the company with other people who have used them. All of the tour guides we used said the internet can make or break their business. The ones I used did not ask for any money up front and they checked the ships itinary to see if any changes had been made to it. Someone above also made a comment saying it was not that much cheaper than Carnivals....We saved about 50-75% on our excursions which worked out to saving HUNDREDS for a group of 6 people. Also, we were offered excursions that Carnival did not offer. Example, we were able to Cave tube 2 caves and Zip line in Belize along with the butterfly tour, a City tour and they provided lunch and a bottle of Cashew wine for $115.