I'm going to suggest a couple other options - actually it might be better do this first one in January first from Mexico City. Fly over to Cabo San Lucas on the Baja Peninsula. Arguably the best large animal diving in Mexico - probably anywhere in this hemisphere except the Galapagos - is the Socorro Islands (Revillagigedos). They're a chain of islands SW of Baja - it takes a liveaboard 24 hours to get there so it's a 10-14 day trip. Not cheap either - starting around $3500. But so popular that you may actually not be able to get space on any of the boats now either. This is excerpted (and shortened) from
Solmar V's website and explains better than I can why you want to:
The Revillagigedos Archipelago, more commonly called Socorro is located in the eastern Pacific Ocean approximately 250 miles south of Cabo San Lucas, Mexico – at the tip of the Baja peninsula. These islands have been compared to the Galapagos Islands in Ecuador or Cocos Island in Costa Rica because of the big animal encounters they provide.
The Revillagigedos Islands consist of 4 islands – San Benedicto Island, Socorro Island, Roca Partida and Clarion. We simply call them Socorro. They are wild, remote and unpredictable and have been called the Mexican Galapagos. This area is famous for up close and personal encounters with the Giant Pacific manta ray, which can grow to 22 feet from wingtip to wingtip. We’ve been interacting with these gentle giants since 1992 and as a result of having worked with several manta researchers over the years, we have extensive ID’s on most of them and special relationships with many of them. We absolutely do not chase or ride the mantas, and we allow our interaction with them to be initiated by the mantas themselves. San Benedicto is by far the best location in the world to experience and photograph these gentle giants. The feeling of a wild animal this large deliberately interacting with you is something you will never forget.
There are lots of sharks in the Revillagigedos Islands - hammerhead schools, white tips, silver tips, silkies, duskies, Galapagos and occasionally tigers. We have encountered up to 7 species of sharks on a single dive! There are several hammerhead cleaning stations that we visit each trip, weather permitting.
We also encounter pods of wild bottlenose dolphin on a regular basis and from January through March, these islands are home to a large population of humpback whales, that come here to breed and calve. We have observed several newborn humpbacks in the years we’ve been fortunate enough to visit these remote and pristine islands. In the last few years the frequency of underwater encounters with humpbacks has increased dramatically...Add to the mix extremely large tuna (the world record yellowfin is from these waters), wahoo, thick schools of jacks and many other big critters along with endemic tropicals found nowhere else in the world,
The boats that do this trip are Solmar V, the Nautilus Explorer, the Nautilus Belle Amie (newest/nicest) and the Rocio Del Mar. Rocio is all sold out thru 2018 - another indication of the popularity of this trip. The others might still have cabins available. Solmar has a Youtube channel and posts weekly trip videos of what their guests see on that specific trip. You almost can't believe the amount of mantas, sharks, dolphins, hammerheads, etc. seen in the short clip. The one from early January 2014 shows humpbacks at the very end.
Another option in that area is to dive near Cabo San Lucas for a couple of days then move up the coast to La Paz and Loreto. I believe (but not sure) you'll have to return to Cabo to get a good flight over to Cancun.
Legendary diver Jacques Cousteau described the Sea of Cortés as the "world's aquarium" and the "Galapagos of North America."
and
At the southern tip of Baja, just 60 miles northeast of Cabo San Lucas, sprawls a marine protected area known as the Cabo Pulmo National Marine Park. Cabo Pulmo's shallow bay gives way to one of three living reefs and the only hard coral reef in North America. One of the most diverse eco-systems in the world, the Cabo Pulmo reef creates a safe harbor for a remarkable variety of captivating sea life such as whales, sharks, manta rays, sea turtles, sea lions and more than 256 species of fish.
El Bajo is a seamount reachable from La Paz. People go there for the Hammerheads.
El Bajo Dive Site - La Paz Baja Mexico - Cortez Club
In the winter months the tidal exchange into the Sea of Cortez brings colder water so the visibility improves since the plankton dies. But it's full wetsuit conditions.
For your second month First fly to Cancun like the others said. From there work your way down the Mexican Riviera ferry over to Cozumel for a week or so etc. Another option is that if you drive down to Chetumal there's a ferry to Belize. It stops at Ambergris Caye which is one of the better known dive destinations in Belize - and very affordable - much of it is walkable. From Ambergris the Great Blue Hole is a daytrip. Maybe you've heard of it?
Great Blue Hole | A Diver's Paradise: The Largest Discovered Underwater Sinkhole
Or take a short flight/different ferry back to Belize City. From there you can fly to Roatan, Honduras on Tropic Air. Roatan is another very good to excellent dive destination. Roatan's West End has very affordable everything - lodging, food, diving (dives are 10/$350) etc. Another walkable area. Coconut Tree Divers has a good general info page about the area:
Roatán, West End | Scuba Diving | Roatan, Bay Islands, Honduras | PADI Assuming you're English, lots of your ex-pat countrymen in that area also. Including the owners of Coconut Tree, PJ and Gaynor. Nice people - Gay knows everything/everyone about the area. Ask her for restaurant reco's if you get there.
have a good trip..I agree with the others - I live in Arizona (borders Mexico) and I won't drive deep into the country any longer. Driving around locally in any resort town seems perfectly safe though - the Mexican government knows where the tourist revenues are generated.
