Puerto Vallarta is a big-resort-town diving hub on Banderas Bay, one of Mexico's largest Pacific bays: granite rocky-reef day-boat diving around the Los Arcos refuge and the Marietas Islands biosphere reserve, with variable plankton-rich visibility, winter humpback whale song audible underwater (December–March), and a scientifically documented oceanic manta aggregation.
Destination info
Conditions, highlights, and the resident marine life.
Conditions
Water and air temperature across the year.
WaterAirDryShoulderWet
Description
Banderas Bay is plankton-rich Eastern Pacific water, and the diving should be judged as such: visibility swings roughly 5–25 m with the season, the reefs are granite boulders, walls, and arches dusted with sponges and pockets of coral rather than coral gardens, and the marquee in-town site, Los Arcos, shares its surface with heavy snorkel- and party-boat traffic. What the bay does well is access and a split personality of seasons. Los Arcos — a cluster of granite islets federally protected as a marine flora and fauna refuge since 1975 and the standard 20-minute day-boat run — sits on the deepest water in the bay (the park's seabed falls away past 480 m), so a beginner can potter around the 10–14 m Aquarium while an experienced buddy drops onto the Devil's Canyon wall on the same boat. From roughly June to October the water is 28–30°C with the year's best visibility; from December into spring the bay cools into the low 20s and greens up with plankton, and that trade buys the megafauna: several hundred humpback whales breed in the bay (official watching season 8 December–23 March, with male song clearly audible on most winter dives), oceanic manta sightings build to a spring peak around April backed by a 397-individual photo-ID catalogue, and the occasional whale shark wanders through. The outer sites — the Marietas Islands national park (declared 2005, UNESCO biosphere reserve 2008, and the site of a well-publicised 2016 overtourism closure), El Morro's tunnel-pierced pinnacles, and remote El Chimo — need calmer seas and are more reliable in the summer-to-autumn window.
Highlights
What makes this dive worth the trip.
Los Arcos de Mismaloya has been federally protected since 1975, when the Secretaría de Industria y Comercio decreed the islets a Zone of Refuge for the Protection of Marine Flora and Fauna — tourism copy often upgrades it to a 1984 'national marine park', but the 1975 refuge decree is the original legal protection, and fishing is banned inside it.
The Marietas Islands are the honest cautionary tale of Banderas Bay tourism: visits to the 'Hidden Beach' (Playa del Amor) exploded from about 27,500 in 2012 to over 127,000 in 2015, coral was dying, and CONANP closed it outright on 9 May 2016. It reopened in late August 2016 under hard caps — 116 visitors per day, 15 people at a time, 30 minutes maximum, no fins or snorkel gear in the beach corridor, and no diving at the beach itself.
The Marietas archipelago joined UNESCO's Man and the Biosphere network in 2008 (15,507 ha, all but 78 ha of it marine). It sits where the California Current, the Costa Rican Coastal Current, and Gulf of California water converge, so Gulf-of-California species mix with central-Pacific ones, and the islands hold some of Mexico's largest seabird nesting colonies.
Marine life
30 species you’re likely to encounter on a dive here.
Dive sites
6 signature sites at this destination.
Los Arcos — El Acuario (The Aquarium)
The sheltered training-and-checkout dive of Puerto Vallarta, on the landward side of the Los Arcos granite islets about 20 minutes by panga from town. A boulder-and-sand bottom in 10–14 m holds dense small-fish life — surgeonfish, snappers, garden eels, zebra and green morays, lobsters, octopus — plus resident Pacific seahorses if your guide knows the spots. Expect snorkel-boat traffic overhead and honest, variable bay visibility rather than gin-clear water.
6–14 mbeginnerDay boatLightVisibility 6–15 m
Los Arcos — El Cañón & La Quijada del Diablo (Devil's Canyon)
The serious side of Los Arcos: on the exposed west face of the islets a vertical wall reported at roughly 250 m (800 ft) falls toward the deepest water in Banderas Bay. The drop-off starts around 18–20 m and the dive itself works the wall between 25 and 35 m past gorgonians, schooling snappers, rays, morays, and turtles, with giant mantas an occasional bonus on the adjacent El Paredón face. Depth and exposure, not current, are what make this an experienced-diver site — same boat ride as the Aquarium, very different dive.
18–35 madvancedDay boatLightVisibility 6–15 m
Islas Marietas
The volcanic Marietas archipelago at the mouth of the bay — national park since 2005, UNESCO biosphere reserve since 2008 — is about an hour's boat ride from Puerto Vallarta or shorter from Punta Mita. Underwater it is arches, spires, tunnels, and caves in 7–23 m with around 115 recorded fish species, turtles, and seasonal manta and (from the boat, December–March) humpback sightings. Suitable for all levels, but temper expectations: average visibility is about 12 m, the surface is busy with tour boats in high season, and access runs under CONANP park rules — the famous Hidden Beach is capped and off-limits to divers.
7–23 mbeginnerDay boatLightVisibility 8–20 m
El Morro
A set of rock pinnacles in open Pacific water on the northwest edge of the bay, about six miles west of the Marietas and roughly 90 minutes by boat — the area's signature advanced trip. The draw is architecture: caves and a roughly 40 m tunnel that pierces the rock, typically entered around 30 m and exited near 18 m, plus walls dropping to 40 m and blue-water exposure that brings giant mantas, the odd whitetip or nurse shark, sea lions, and in lucky winters a whale shark. Operators sensibly ask for solid experience (commonly 50+ logged dives), and trips are weather-dependent — the open-ocean sites get rough and unreliable from late November into June.
12–40 madvancedDay boatModerateVisibility 12–30 m
Majahuitas
A boat-only cove on the jungly south shore between Quimixto and Yelapa, about 45 minutes out — the relaxed second-tank or beginner alternative to the headline sites. Easy sloping reef and sand from about 5 to 27 m with extensive garden-eel fields, rays, turtles, and a couple of small sunken panga boats; minimal current makes it a reliable all-levels site most of the year. It is pleasant rather than spectacular — come for calm conditions and critters, not big animals.
5–27 mbeginnerDay boatLightVisibility 8–25 m
El Chimo (Las Iglesias)
The southwesternmost dive area of Banderas Bay, off a tiny fishing village 70–80 minutes by boat — named for rock formations whose twin openings recall a church portico. Deep rocky reef from about 18 to 43 m with sponges, coral heads, big schools of reef fish, turtles, and a deserved reputation as a giant-manta encounter spot; boat traffic is light because few operators run this far. Operators restrict it to experienced divers (50+ dives) for the depth and exposure, and like all the outer sites it is at the mercy of sea state outside the summer calm.
18–43 madvancedDay boatModerateVisibility 9–20 m
Where to dive & stay
Local dive centers, resorts, and hotels.
Featured operators coming soon
Verified dive centers, resorts, and hotels around Puerto Vallarta will list here — pricing, photos, and direct contact.
