If you've never been to Cozumel before, let me suggest that you do NOT need a Resort that includes diving - or anything else, for that matter. To me, the second biggest allure of Cozumel, after the quality of diving, of course, is the great quality and variety of the restaurants available, and the friendliness of the people. I am all for AI resorts in locations where they are the best option - like Jamaica, where safety concerns might induce tourists to want to spend their entire vacation in a fenced in enclosure, or destinations where the local restaurant scene is spotty at best. But Cozumel has much too much to offer, IMHO, to spend your vacation in an isolated resort. That is why, in over 20 years of coming to Cozumel, I have only once stayed at an AI (Hotel Cozumel) and ONLY because that was part of the package deal for the Scuba Board Cozumel Invasion in 2012. I still ended up leaving the Resort for lunch and dinner 5 out of the 7 days I was there. I don't do AI on Cozumel, and unless you have a compelling reason for doing so, like small kids that can eat whenever they want so you don't have to worry, or you drink like a fish so you are going to get your money's worth at the bar, I don't recommend AI resorts for others coming to Cozumel.
When it comes to Hotels or Resorts, I've never stayed at any of the far south resorts -Secrets, Aura, Occidental, etc., as I really like eating at the many fine restaurants, most of which are Downtown San Miguel, and the Southern Resorts are just too isolated for me. It's a long ride into town, and very expensive if you have to rely on taxis both ways. I've also never stayed at any of the Hotels or Resorts north of Town - most all of the Dive locations are south, and most Dive Ops won't pick you up from the North Hotel Zone. That leaves Downtown Hotels, like Casa Mexicana, Suites Bahia, Suites Colonial, and lots of others, in-town B&Bs, or Hotels and Resorts south of town. Those nearest to town, an easy walk if you want to avoid taxi fares, include Cozumel Palace, very expensive, All Inclusive, and I WILL NOT STAY THERE OR GIVE THEM ONE THIN PESO OF MY MONEY, EVER (personal reasons; the owners are thieves who completely ripped me off when they bought Plaza Las Glorias out of bankruptcy. They were required to assume the Time Share contracts, but they ignored the contracts and stiffed the owners). Then there is Hotel Cozumel, which is a nice Hotel, huge pool, big comfortable rooms, and not a bad walk into town. Hotel Cozumel has an AI Option, but don't do it (unless you plan on drinking a LOT), in my opinion the food is TERRIBLE. But it is not a bad option if you do the European Plan. A lot farther south, near the International Pier, are places like Casa Del Mar, which I have stayed at several times, or La Cieba/El Cid, which I've stayed at once long, long ago (it was getting a bit aged then, but I understand that they did a lot of remodeling, so I have no idea what it's like now). I like that area - lots of Dive Op options, not bad shore diving, and you are close to the Marine Park so the boat rides to dive sites are shorter. Downside is that it is an $8 cab ride each way to Downtown, so if you plan on eating at the restaurants, either rent a car or budget a lot for cab rides,
The best recommendation I can make is to do your vacation ala carte - pick a Hotel or Resort that fits your needs/desires, figure out just what you want from a dive op, narrow your list to 2-4 possibilities, then check the reviews here and check their web page to pick your favorite, and spend your food money at the local restaurants - you can find a lot of great choices in just about every price range.
