Snorkeling and Diving in Banderas Bay: Los Arcos, Marietas, and Majahuitas

Banderas Bay hides a whole second world below the surface. Granite arches riddled with caves and tunnels, an offshore island biosphere, quiet reef coves reachable only by boat, and, in winter, the sound of humpback whales singing through the water while you swim. This guide covers the three headline sites for snorkeling and diving, Los Arcos, the Marietas Islands, and Majahuitas, plus a shore-snorkel option that needs no boat, and the honest practical details on gear, tides, seasons, and what the visibility is really like. This is a nutrient-rich Pacific bay, not the Caribbean, and knowing that going in is the difference between a great day and a disappointed one.

Los Arcos Marine National Park

Los Arcos is the crown jewel of snorkeling around Puerto Vallarta, a cluster of granite islets rising out of the bay about 12 kilometers south of town, just off Mismaloya. Protected since the 1970s and made a national marine park in 1984, it is a genuine reserve, which is why the marine life is so rich. The rocks are carved with dramatic arches, sea caves, and underwater tunnels you can swim, kayak, or even motor through, and the water around them is shallow and sheltered near the islets before dropping off steeply into the deep.

For snorkelers, this is the sweet spot. In the shallows near the rocks, roughly 30 feet and less, you drift over king angelfish, sergeant majors, pufferfish, and parrotfish, with moray eels tucked into crevices, octopus changing color on the rock, and sea turtles and eagle rays passing through. Overhead, the islets are alive with seabirds. For certified divers, Los Arcos delivers a second act: the shallow reef and arches are beginner-friendly, while the western side falls away in a sheer wall, and the nearby deep sites known as El Bajo and Devil's Canyon plunge into the deepest part of the entire bay, well past what recreational limits allow. Those deep sites are for advanced divers only, and they are where you find the bigger animals, giant morays, manta rays, and the occasional seahorse.

As a protected park, the rules are simple and firm: no fishing, no taking anything, not a shell or a rock, and no touching or disturbing the coral, the wildlife, or the birds. Los Arcos is reachable only by water, most easily by a 5 to 10 minute panga ride from Mismaloya, by water taxi from Boca de Tomatlan, or on a guided tour from the Los Muertos Pier. Swimming out from shore is not advised because of currents and boat traffic.

The Marietas Islands

Out at the northwestern mouth of the bay, off Punta de Mita, the Marietas Islands are a protected biosphere reserve and one of the most rewarding snorkel sites in the region. The clear, sheltered water around the islands holds well over a hundred species of tropical fish along with sea turtles, octopus, and manta and eagle rays, and the cliffs above are a rare nesting colony of blue-footed boobies, so the wildlife is spectacular above and below the surface. The islands are most famous for the Hidden Beach, tucked inside a collapsed crater, but access to that beach is tightly limited by permit, cap, and a real open-water swim. Because the rules are strict and specific, we cover them in full in our dedicated guide to the Islas Marietas and the Hidden Beach. For snorkeling, the key point is that the standard Marietas tour, with its reef and its birds, is superb on its own, whether or not you make it into the Hidden Beach.

Majahuitas

For a quieter underwater day, Majahuitas is the pick. It is a small, boat-only cove on the bay's wild south shore, near Quimixto and Las Animas, and because it is not a formal reserve it sees far fewer visitors than Los Arcos, so you may have the reef largely to yourself. The water is calm and protected, the reef sits at a gentle, snorkel-friendly depth, and the residents include sea turtles, stingrays, spotted eagle rays, and clouds of tropical fish. Dolphins often escort the boats on the way there. You reach it by water taxi from Boca de Tomatlan or Mismaloya, or as part of a south-shore tour, and it pairs naturally with a beach day.

Conchas Chinas and the winter whale-song bonus

Not every snorkel needs a boat. Just south of the Zona Romantica, the rocky coves of Conchas Chinas are the best shore-based option in town, a series of natural rock pools and sheltered pockets where you can wade in and snorkel over crabs, small tropical fish, anemones, and mollusks. The catch is in the timing and the footing: it is a rocky, tide-pool spot rather than a reef, so go at low tide when the pools are calm and accessible, and wear water shoes. Visibility is modest and variable, but for a free, no-boat swim a short walk or bus ride from downtown, it is a lovely way to spend a morning.

Then there is the winter bonus that no other season offers. From roughly December through March, humpback whales fill Banderas Bay to breed, and the males sing. If you are snorkeling or diving anywhere in the bay while they are around, you can often hear that haunting song carrying through the water, a sound you feel as much as hear. Divers experience it most clearly, submerged and still, and it turns an ordinary dive into something people remember for life. Our full guide to whale watching in Banderas Bay covers the season in depth.

Planning your underwater day: gear, tides, and honest visibility

A little planning makes all the difference underwater. You can go the do-it-yourself route, taking a bus to Mismaloya and hiring a panga to Los Arcos with your own mask and fins, or join a guided snorkel or dive tour that handles the boat, the gear, and the guiding; the boat-only sites like Los Arcos, Majahuitas, and the Marietas really do need a boat, while Conchas Chinas is the shore option. Puerto Vallarta has plenty of PADI dive shops for everyone from first-timers doing a Discover Scuba session to certified divers heading for the deep wall.

On gear and comfort, let the season guide you. In the cool, dry winter months the water sits in the mid-60s to mid-70s Fahrenheit, so a 3 to 5 millimeter wetsuit is worth it, while the warm season, from about June through October, runs into the low-to-mid 80s and needs little more than a swimsuit or a shorty. Wear only reef-safe, biodegradable sunscreen, applied well before you get in, or skip it in favor of a rash guard; it is strongly encouraged everywhere and strictly required at the Marietas park, where regular sunscreen is banned at the entrance.

Finally, an honest word on visibility, because managing expectations is the whole game here. Banderas Bay is a living, nutrient-rich Pacific bay, not a Caribbean lagoon, so it is rarely crystal clear, and clarity genuinely swings with conditions rather than following one simple rule. On the calmest, best days you might get 60 feet or more of visibility, occasionally over 100; on off days it can drop to 15 to 50 feet. Winter delivers the calmest seas and the biggest marine life but cooler, sometimes greener plankton-rich water, while the warm season can be beautifully clear except right after heavy rain, when runoff clouds the water near shore and the river mouths. The reliable constant is the morning: go early, when the water is calmest and the light is best, and you give yourself the finest conditions the bay has to offer that day.

Frequently asked questions