The rent a car option is good - IF you know the area, are confident of driving under very different conditions than you are used to and you understand you MUST have insurance in most places (e.g. Mexico legally requires insurance for liability) and without insurance, you are quite likely to be detained until the issue is "straightened out" - can be days, weeks.

As well, what we call "local knowledge" is also on occasions invaluable, I recall driving into a petrol / gasoline station in Belize City only to recognize some very serious gang members and carefully drive on. Many places that seem idyllic have a poison pill possibility - areas you should absolutely not visit, rampant pilferage from cars (Bonaire comes to mind), traffic jam prone places, military checkpoints, etc. A rental agency is not going to spend much time educating you, a local driver or guide will know all about these things.

The Belize Zoo is truly spectacular, but out of town - natural habitats and local critters you are not likely to see most places. There are archaeological sites, etc.

Be aware activities are entirely at your own risk - there are no USOSHA or other regulatory agencies in many countries that are inspecting and licensing any of the parasailing, zipline, etc. and though I do not want to be a party pooper, you will become your own expert and inspector here, and liability laws in most countries do not protect you in case of injury. This is probably applicable to shipboard contracted tours as well - the cruise line will generally not stand behind any tour supplier, it's all on you. (They always claim to have inspected, etc. and then issue a strong disclaimer...:p)

OTOH, hiring a driver for four to six hours can be cheaper than renting a car, and the driver takes the hit for accidents / incidents. There are also, as others have indicated, local tour providers that are reputable.

thanks, answered many of the questions i had myself

Just a quick follow-up:

1) For Cozumel, we hired a cab through Eduardo Esquer. Although Eduardo was not our driver, he had one lined up for us who took us around the island, including to the San Gervasio ruins, a beach on the south end of the island, and some shopping. While the taxi service he provided was perfectly fine, I think he was only necessary for transport to San Gervasio and back - the other places had cabs coming by, and it would have just been cheaper to hire them as needed, or even renting a car on our own.

2) For Belize we booked a tour through the cruise line because I couldn't find an equivalent tour of what we wanted to do online. You do get a slightly higher priority with the tenders if booked through the cruise line which may be better for ports with shorter stays like Grand Cayman.

3) We booked a kayak and snorkeling tour through ShoreTrips.com in Roatan. This excursion was fantastic and I highly recommend it. ShoreTrips is a third-party booking agency and the actual tour was run by Subway Watersports - however the price is identical booking with them.

4) We had nothing prebooked for Grand Cayman and after seeing the docks at the previous places, we determined we could easily find an excursion of our own upon arrival. Unfortunately the other half wasn't feeling too well that morning so we just showed up around 1p and wandered around town for a few hours.

Cliff Notes: I was quite happy with the results I had with booking outside of the cruise-sponsored ones and recommend others do the same!

Agree with all that MastaHanky has advised and will only add that some ports of call such as Belize the cruise ships anchor offshore because of a reef and tender you to shore which can take up some of the time for your port of call stop.

Also I did some research on Cruise Critic and found that the day my Holland America cruise in January '12 stopped in Belize there were, IIRC, 5 other cruise ships all in port at the same time making it harder to find availability through a local tour company so I opted to book onboard.

As with much regarding travel there is no hard & fast rule that applies to all travellers in all situations so you have to find what works for you. Happy sails! :)

Also, be aware that when tendering to a port (at least with NCL), only passengers who have ship booked excursions can leave first. This can result in a significant wait for the others. We also ran into this when we docked in Quebec City, and almost missed our privately booked excursion.


DD

Suite guests too- I stayed in the penthouse last cruise and we were escorted to the tender whenever we liked.

It does add value to use a ships tour on a short stay tender port, but that's the rare case. Personally I'd always rather do a private tour- many times you end up with the ship group anyway as they use the same service provider!