My wife and I are planning a cruise to Grand Cayman, Roatan, Belize City and Cozumel.
Cayman and
Cozumel have the best surface diversions. Shopping, beaches, bars, etc.
Roatan is a bit tribal by comparison, the cruise ship will undoubtedly hook her up with jungle canopy zip-line tours, Iguana Farm, West End (Bars, Beaches and Guatemalan Import Souveniers), and the cruise ship mecca- the Dolphin Pester. For that, you don't even have to snorkel- you can just stand there in three feet of weater and Flipper will come over and give you a little
somthin' somethin'.
Belize is a non-starter both for diving as well as shore excursions. I would advise you to both do what shore excursions are offered, maybe they'll do the river thru the cave tubing tour. The Belize Zoo is... there.
Do not misunderstand- the diving in Belize is phenomenal! It's just that you really cant access it in a timely manner from the far away cruise ship zone or Belize City. If you are diving Belize, you do it a week at a time. It is, again, must do diving~ just not from a cruise ship.
Cozumel might be ideal for both your needs allowing you to go your separate ways. Great land diversions and they dive-ops will show you a great time. She can be easily entertained in Cozumel. Parasailing, jet ski rentals and just sunning on the sand... with wait staff! Lots and lots of bars and restaurants, too. On the other hand,
Cozumel would be a great place for a "together day".
Cayman has the ultimate cruise ship signature dive- Stingray City. Worth doing, at least once, and if your bride can't be amused by the Turtle Farm, getting her passport stamped in "Hell", or sucking down blender smoothies with parasols beside the pool and/or beach... Deal with it later- you go do the Stingray Dive. An evening dinner date in Cayman would be well advised, but you will not have that option.
In
Roatan, if she wants to do the Dolphin thing, you could dive at the same resort, AKR. I wouldn't make that a selection consideration, as you really won't see each other or be on the same bus. The ship will offer several variants of the dive outing, pick what looks good. Understand- no dive op is going to take you anywhere that they wouldn't take any first day new arrival guest. They don't know you from Adam, so they're going to handle you like they do everyone on their first day of a week of diving.
In
Roatan, if she selects the Dolphin deal, the other half of the day could easily be spent at West End (the Bars, beaches and marginal shopping). They are building something new for "pod people" (get used to it!) called Mahogany Bay which will have shopping,
their own Dolphins, and eventually Cruise Ship docks. It is located just East of the Airport, on the South side, in Dixon Cove.
There is no "one answer" to this often asked question.