I have traveled to eastern Mexico on many occasions to dive on the islands of Cozumel and Isla Mujeres, and the mainland area known as the Riviera Maya. I was lucky to travel to Isla Mujeres (see my review) and the Riviera Maya (another review) in January 2020 just before the world was hit with covid19. The Yucatan peninsula is dotted with over 6000 cenotes, or sink holes, many of which are diveable. There's a large concentration of cenotes along the Riviera Maya in the areas of Playa del Carmen, Akumal, and Tulum. Dive operators in any of these cities can take you cenote diving.
Many of these cenotes have very interesting names, such as Taj Mahal, Dream Gate, Ponderosa, Garden of Eden, Temple of Doom, Carwash, Dos Ojos, and Pet Cemetery. Even though these are underwater caves, sport divers can dive them without a Cave Diver certification. The dives are called cavern dives, and even though most have an overhead, you will never lose sight of the entrance. The cenotes are essentially fresh water, but because of their connection via underwater rivers, in some of the cenotes salt water will seep in and cause a phenomenon called a halocline. This is a mixing of fresh water and salt water, and because of the density difference between the two, a zone of the mixed water causes an ethereal effect while passing through it. It looks as though everything seems out of focus. You will find a halocline in many of the cenotes. At least two different cenotes, Angelita and El Pit, have another phenomenon that appears like a cloud below you after entering the water. These are actually clouds formed by hydrogen sulfide gas caused by decaying leaves and other plant materials. You can penetrate the clouds and drop down under them for a totally different experience. At least one of these two is a must-do dive. Many of the cenotes are adorned with stalactites and stalagmites, leftovers from ancient times when they were filled with air.
Expect the water in the cenotes to be much cooler than the ocean. I was comfortable in a 3mm wetsuit, but my buddy was cold, although she does get cold much easier than I do. You also won't see much in the way of critters. The fish consist mostly of smaller, fresh water species like mollies, catfish, tetras, cichlids, etc. In many cenotes you will see an underwater sign consisting of a skull and crossbones with warnings: “Do not continue beyond this point. Certified cave divers only”. Many people believe that these cenotes are all joined by underwater rivers and cave divers have penetrated some caves for miles.
Most, if not all, of the cenotes that I have dived (well over a dozen) require an entrance fee, which was included in the price, along with transportation, lunch, and a cave certified guide. Some are more developed than others, with picnic tables, restrooms, gear changing tables and other amenities. These will attract more swimmers and tourists, but they never interfere with the dives because you make a partial penetration.
If you're looking for a new scuba experience, travel to the Riviera Maya and try Cenote diving. You won’t be disappointed!

We traveled to Baja California Sur to dive in both the Pacific and the Sea of Cortez in the same trip. After diving at lands end, where the two meet, the remainder of our diving was done in the Sea of Cortez. We dove in an area called “the corridor". It consists of shallow reefs with schools of fish, moray eels, invertebrates, etc. We also visited a dive site with a phenomenon called a “sand fall". It’s like a waterfall, but underwater and it’s sand cascading down the reef. After dives in this area, we saw a humpback whale migrating north into the Sea of Cortez, toward the area we were headed to next, Cabo Pulmo. Cabo Pulmo is a strictly enforced marine park where the dive sites seem to be untouched. We saw massive schools of fish, huge groupers, loads of invertebrates, and close encounters with bull sharks. Overall, we found the diving here to be excellent. We can’t wait to return to the Sea of Cortez to dive around the areas of La Paz and Loreto.

We elected to stay here because of the location at the marina. The dive shop I was using is also located here. Our room was very spacious, modern, and clean. The complex was quiet at night, even though it's only a short walking distance to restaurants, bars, and clubs. Tesoro Los Cabos has a large pool with two hot tubs and a swim up bar overlooking the marina. There are several restaurants on the property, although a couple were temporarily closed. We ate lunch in the Vista Roof restaurant and the food was top notch. There's a gym with a nice workout area that will accommodate a lot of people and there was no waiting to use any of the equipment. TLC also has a full service spa if you need a massage after a few days of diving. The “downtown” area is a short walk where you can find more restaurants, clubs, liquor stores, grocery stores, etc. We rated everything at this resort as excellent. We recommend Tesoro Los Cabos Hotel and will return again.

We traveled to Maui in September as two couples; two divers and two non-divers. We rented a 2 bedroom condo outside of Lahaina and drove there in a rental car we picked up at the airport. After chilling by the pool for a day, we decided to do some scuba diving. We reserved 3 days at a dive shop in downtown Lahaina, walking distance from the boat. We customized our dive package and chose the Molokini Backwall dive the first day. The diver operator provided a light breakfast before we headed down to the dock. It's a drift dive on a near-vertical wall on the back side of the submerged Molokini volcano crater. We drifted between 70 and 90 feet deep while watching the beautiful fish on the wall side. Many of these fish are endemic to Hawaii and found nowhere else in the world. About 20 minutes into the dive, we were surprised to see a pod of dolphins swim past in the blue water. Toward the end of the dive, we spotted a whitetip reef shark. During the surface interval, we ate the included lunch and the boat was moved to the corner of the crater. We started this drift dive just outside and made our way to the inside of the crater. This area has fantastic hard corals and we saw lots of fish, a moray, and a large ray. The water here was very warm and clear. There were a lot of snorkelers above us and we were able to wave to each other. Cookies were served on the ride back. These were two enjoyable dives.

Day two was the Hammerhead trip to Molokai. After a boat trip of about 1 hour, we did our first drift dive looking for scalloped hammerheads. About 25 minutes into the dive, we spotted several. It was exciting to see them, but we were hoping to see a larger congregation. Beggars can't be choosers and seeing even one Hammerhead is a thrill. After lunch, we made a second dive which was very much like the first one. We did see a small group of hammers and enjoyed the show. Once the diving was done, the weather was so perfect, the boat crew went out of their way to cruise around the island so we could see parts that divers and tourists rarely see. Even the crew was excited to be cruising these parts of the island under such pristine weather and ocean conditions. Breakfast, lunch, and cookies were included again.

Day three was a 3 tank safari to the far side of Lanai. This trip included three drift dives on sites less frequently visited than regular trips. The underwater topography is beautiful with really diverse reefs, sheer walls, and some swim-throughs. These were excellent dives where we spotted dolphins, whitetips, turtles, and tons of colorful reef fish. The captain decided to continue around the island instead of returning the way we came. As we started to turn the corner for the crossing back to Lanai, it was obvious the wind had come up and it was too rough to continue. We eventually turned around and went back the way we came. It was a rough ride and my buddy was seasick the whole ride back. Bummer for him! The same meals included, but I'm sure he wished he hadn't eaten at all.

The rest of the trip was spent on the topside with our wives. We drove the road to Hana, stopping along the way to visit some waterfalls, hike in a bamboo forest, and once we got to Hana, we spent time at the seven sacred pools. On other days we found some excellent snorkeling beaches and did some sunbathing. We found some really good restaurants and had fun shopping for souvenirs.

Bottom line: Maui is a place for sun, fun, and great diving. No passport required for US citizens. Be sure to have shave ice in Lanai with all the extras. You won't be disappointed.