A cenote is a natural sinkhole formed when limestone bedrock collapses and exposes the groundwater below. The Yucatan Peninsula has over 6,000 cenotes, all connected by the world's largest underground river system. The water is crystal-clear, cold (around 24°C year-round), and fed by ancient rainwater filtered through limestone for thousands of years.

Are cenotes safe to swim in?

Open cenotes are generally safe for swimmers of all levels, though some are very deep. Semi-open and cave cenotes require more caution — cave systems require an experienced guide, and solo diving is never allowed. All cenotes prohibit chemical sunscreen (reef-safe biodegradable only), and alcohol before swimming is strongly discouraged. Always wear a life jacket if offered at open cenotes, regardless of swimming ability.

What sunscreen can I use in cenotes?

Reef-safe, biodegradable sunscreen only. This is a legal requirement in the Yucatan — not just a suggestion. Regular sunscreen containing oxybenzone or octinoxate is prohibited. Most cenotes provide biodegradable sunscreen on-site, or you can buy it in Tulum, Playa del Carmen, and most pharmacies throughout the Yucatan. Getting caught with chemical sunscreen can result in a fine of around 200 MXN.

How do I get to cenotes without a car?

Colectivos (shared vans) run between most Yucatan towns and pass near major cenotes on their routes. From Tulum, Gran Cenote and Dos Ojos are 5-8km away — reachable by bike rental. From Valladolid, colectivos and taxis get you to Suytun, Dzitnup, and Samula cheaply. From Playa del Carmen, tour operators run full-day cenote trips. Some cenotes like Ik Kil are directly on the Chichen Itza route and easy to add as a stop.

What should I bring to a cenote?

Biodegradable sunscreen (required), reef shoes or water shoes (rocks can be sharp), an underwater camera or waterproof phone case, a change of clothes, and cash for entry fees (most cenotes don't accept cards). A rash guard is recommended for extended swimming. Most cenotes have lockers for a small fee. Life jackets are usually available free or cheaply at the entry point.

Mexico Cenotes Guide 2026: Types, Safety & How to Visit

Crystal clear cenote water in the Yucatan Peninsula Mexico

No other place on Earth has cenotes like the Yucatan Peninsula. More than 6,000 of these natural freshwater sinkholes dot the landscape between Cancún and the Guatemalan border — all connected by the world’s longest underwater cave system. Swimming in a cenote is one of the defining experiences of traveling Mexico, but it comes with real safety considerations, legal requirements, and context that most travel guides skip.

This guide covers what cenotes actually are, the science behind why the Yucatan has so many, how to visit safely, the reef-safe sunscreen law, and the best cenotes organized by region and skill level.

What Is a Cenote?

The word cenote comes from the Maya word ts’onot, meaning “sacred well.” The Maya considered cenotes sacred because they were — for a civilization living on a peninsula with no rivers and no surface freshwater — the only source of drinking water. They served as community water sources, ceremonial sites, and occasionally as places of sacrifice.

Scientifically, a cenote is a collapsed limestone sinkhole that exposes the water table below. Here’s how it forms:

Rainwater, slightly acidic from absorbing CO₂ as it falls, percolates down through porous limestone.
Over thousands of years, the slightly acidic water dissolves the limestone, creating underground caverns.
When the cavern ceiling becomes too thin to support its own weight, it collapses.
The collapse exposes the water table — and creates a cenote.

The water itself is extraordinary: crystal-clear, around 24°C year-round regardless of outside temperature, and filtered through limestone for thousands of years before it arrives in the cenote.

Why Does the Yucatan Have 6,000+ Cenotes?

Two reasons: geology and a meteor.

The geology: The Yucatan Peninsula is almost entirely flat limestone. Unlike most of Mexico, it has no rivers. All the freshwater that falls as rain goes underground, creating a vast network of underground rivers and caves instead of surface drainage. This system is the perfect environment for cenote formation at massive scale.

The Chicxulub meteor: 66 million years ago, the asteroid that ended the dinosaurs struck the Yucatan Peninsula, at what is now Chicxulub near Mérida. The impact created a massive crater roughly 180km in diameter. The ring of the crater is still visible today as a slight arc in the landscape — and the highest concentration of cenotes in the Yucatan follows that arc almost perfectly. The impact shattered and fractured the limestone bedrock in a ring pattern, creating the ideal conditions for cenote formation along the crater’s edge.

You can see this from satellite imagery: the “Ring of Cenotes” traces the Chicxulub crater edge.

The Sac Actun System: What’s Below You

The Sac Actun system is the world’s longest underwater cave. As of the most recent mapping, it extends at least 347 kilometers — and possibly much further, since exploration is ongoing. It connects to other cave systems (Sistema Dos Ojos, Sistema Ox Bel Ha) in a network that’s the largest underwater cave system on Earth.

When you swim in a cenote, you are entering the Sac Actun system. The “hole” in the surface connects to passages, caves, and tunnels that extend hundreds of kilometers in every direction underground.

At least 10 cenotes accessible to the public are officially entries into the Sac Actun system. Dos Ojos near Tulum is one of the most famous.

Types of Cenotes

Open cenote in the Yucatan with sunlight entering from above

Open Cenotes (Type 1)

The limestone ceiling has fully collapsed, leaving an open-air pool. Sunlight enters directly, making these the most photogenic and easiest to access. Most popular tourist cenotes are open type.

Experience required: None. Suitable for all ages and swimming levels. Life jackets available.

Examples: Gran Cenote (near Tulum), Ik Kil (near Chichen Itza), Suytun (near Valladolid), Balankanche

Semi-Open Cenotes (Type 2)

The ceiling has partially collapsed — there’s some open sky but also cave sections. These offer a mix of sunlit and cave zones, often with dramatic light shafts cutting through the darkness.

Experience required: Moderate swimming ability. Cave sections require a guide.

Examples: Cenote Dos Ojos (cave and open sections), Cenote Azul (Bacalar area), Aktun Chen

Cave Cenotes (Type 3)

The ceiling is intact — you enter through an opening and swim in total darkness (except your lights). These are the most dramatic and the most dangerous. Proper cave diving requires specialized training and equipment; snorkeling in guided cave sections is possible at some.

Experience required: Open water certified for diving sections; guided snorkel for accessible sections; do not enter unguided.

Examples: Cenote Angelita (dive only, 60m), Dzitnup and Samula (guided snorkel possible), Chaak-Tun

Safety Rules

These aren’t suggestions. Cave systems kill people who ignore them.

Never dive solo. This is the absolute rule for cave cenotes. Divers die in cave systems every year, usually because they went in alone, ran low on air, and had no one to help.
Always use a guide for cave sections. Cave diving requires specific training (PADI or TDI cave certification). For snorkeling in cave sections, a certified guide who knows the system is required.
Buddy system for open cenotes. Even in open cenotes, swim with someone. Some are very deep (30–50m). The cold thermocline can cause cramps.
No alcohol before swimming. This seems obvious, but cenote towns are full of bars. Alcohol impairs judgment in cave systems in ways that can be fatal.
Respect depth. Many cenotes that look like a 5m pool are actually 30–60m deep. The water clarity makes depth deceptive.
Tell someone your plans. If visiting a remote cenote, tell your accommodation where you’re going.
Wear a life jacket if offered. Most cenote operators offer them free or for a small fee. There’s no reason to refuse.

The Reef-Safe Sunscreen Law

This is a legal requirement, not a preference.

Since 2021, the state of Quintana Roo (which covers Cancún, Playa del Carmen, Tulum, and most tourist cenotes) has banned chemical sunscreen in cenotes, beaches, and natural water bodies. The law requires reef-safe, biodegradable sunscreen only.

Why it matters: Chemical UV filters — particularly oxybenzone and octinoxate — are absorbed by the water and damage the microbiome of the cenote ecosystem. The underground cave system connects to coral reefs offshore, so what goes into a cenote eventually reaches the ocean.

What to buy: Look for mineral sunscreen (zinc oxide or titanium dioxide as the active ingredient). Most pharmacies in Tulum, Playa del Carmen, and Cancún carry biodegradable options. Many cenotes sell it at the entrance.

The fine: Getting caught with chemical sunscreen can result in a fine of around 200 MXN. More importantly, cenote staff often ask you to wash off before entering.

Cenotes by Type Table

Cenote	Type	Entry Fee	Skill Level	Notes
Gran Cenote	Open/semi	150 MXN	Beginner	Halocline, snorkel included
Dos Ojos	Cave/open	100 MXN	Moderate	Sac Actun entry point
Angelita	Cave	Dive only	Expert diver	60m, H₂S cloud at 30m
Suytun	Open	200 MXN	Beginner	Instagram platform
Ik Kil	Open	180 MXN	Beginner	Cliff jump 28m
Dzitnup	Cave	80 MXN	Beginner (guided)	Underground, blue hole
Samula	Cave	80 MXN	Beginner (guided)	Twin to Dzitnup
Zaci	Open	50 MXN	Beginner	In Valladolid town
Chaak-Tun	Cave	250 MXN	Moderate	2km from Playa del Carmen
Yokdzonot	Open	80 MXN	Beginner	Local community-run

Best Cenotes by Region

Near Tulum

Gran Cenote — 6km from Tulum town, this is the most accessible high-quality cenote for non-divers. The water is exceptionally clear, the halocline (where salt water meets fresh water) creates a visible shimmering layer, and snorkel equipment is included in the entry fee of approximately 150 MXN. Get there when it opens (8am) — by midday the tour groups arrive.

Cenote Angelita — One of the most extraordinary dives in Mexico. At 30 meters depth, a hydrogen sulfide cloud creates what looks like an underground river running through the cenote. Stalactites hang below you into the cloud. Trees protrude from the “river.” This is dive-only (60m certified recommended), not for snorkelers. There are multiple guides and dive shops in Tulum that run Angelita trips.

Dos Ojos — The name means “Two Eyes” — two connected cenotes that are both entry points to the Sac Actun system. This is one of the best cave snorkeling experiences available to non-divers: guided snorkel tours navigate by flashlight through the bat cave section and into passages filled with stalactites and stalagmites. Entry around 100 MXN; guided cave snorkel tours extra.

Aktun Chen — A cave cenote within a nature park, guided tours only. Less crowded than the Tulum cenotes, includes cave walks above water as well as swimming.

Near Valladolid

Cenote Suytun — The most Instagram-famous cenote in Mexico. A stone platform surrounded by water with a circular skylight above creates a perfect natural spotlight. It’s beautiful in person, but it’s also crowded — the platform holds about 10 people at a time and the cenote is small. Entry around 200 MXN. Worth it for the experience; don’t expect to have it to yourself.

Samula and Dzitnup — Two cave cenotes 500 meters apart, 6km west of Valladolid. Both are underground — you descend stairs into a cave and find a luminous blue hole illuminated by a shaft of sunlight through the ceiling. Tree roots hang 50–60 meters down from the ceiling to reach the water. Guided tours take small groups through. Entry approximately 80 MXN each.

Cenote Zaci — Right in the center of Valladolid town, this cenote requires no transport and costs only about 50 MXN to enter. It’s a large open cenote with a viewing platform and swimming area. Note: There are crocodiles in Zaci — small ones, rarely seen, but the sign at the entrance acknowledges their presence. No attacks on record, but worth knowing.

Near Chichen Itza

Ik Kil — The most visited cenote in Mexico, directly on the route between Mérida and Chichen Itza. It’s also genuinely spectacular: a perfectly circular open cenote with waterfalls of hanging vines, cliff jump platforms at heights of 7 and 28 meters, and crystal water despite the crowds. Entry around 180 MXN. Expect tour groups; arrive early.

Yokdzonot — A community-run cenote a few kilometers off the main highway near Chichen Itza. Far fewer tourists, lower entry fee, and the income directly supports the local Maya community. A good alternative to Ik Kil if you want a calmer experience.

Near Playa del Carmen

Chaak-Tun — Approximately 2km from Playa del Carmen’s main beach, Chaak-Tun is a cave cenote with guided tours only. It consists of two pools connected by underwater passages. Entry around 250 MXN, includes a guide. One of the few major cenotes within walking or cycling distance of a major tourist hub.

Río Secreto — A guided cave float experience rather than a traditional cenote. You walk and swim through an underground river passage with headlamps provided, past extraordinary stalactite formations. Pricier than most cenotes (around 900 MXN per person for the full experience) but genuinely memorable and well-operated.

Bacalar Area

Cenote Esmeralda — Free access, no facilities, just a beautiful freshwater pool in the jungle south of Bacalar. Worth combining with a visit to the Bacalar lagoon.

Cenote Azul (Bacalar) — Different from the Valladolid Cenote Azul — this one sits directly adjacent to the Laguna de Bacalar in the town itself. One of the deepest cenotes in the Yucatan (over 90 meters), with a restaurant and bar on the edge. Free or low entry on the public side; restaurant side charges more.

How to Get to Cenotes Without a Car

Tulum cenotes (Gran Cenote, Dos Ojos): Rent a bicycle in Tulum town — they’re 5–8km from the main strip, along a flat road. Bike rental is around 150–200 MXN per day. Taxis are also cheap.

Valladolid cenotes: Colectivos from Valladolid’s main terminal pass near Dzitnup and Samula. For Suytun, a taxi from town is about 100 MXN round trip.

Ik Kil: It’s on the main highway between Mérida and Cancún. Every tour to Chichen Itza stops here, or ADO buses will drop you at the entrance.

Playa del Carmen: Most tour operators run full-day cenote tours from PDC for around 800–1,200 MXN including transport, lunch, and two or three cenotes.

General tip: Mexican colectivos (shared vans) are the backbone of local transport in the Yucatan. They’re cheap (10–50 MXN for most local routes) and run frequently between towns. Ask your accommodation which colectivo route passes nearest your target cenote.

What to Bring

Biodegradable sunscreen — required, not optional. Buy before you arrive if you can.
Reef shoes or water shoes — the rocks entering cenotes can be sharp and slippery.
Underwater camera — the GoPro-style waterproof cameras are worth it here. Visibility in cenotes is 30–100 meters.
Change of clothes — you will be wet.
Cash — nearly all cenotes are cash only. Bring enough for entry, lockers, food, and the biodegradable sunscreen sold at the entrance.
Snorkel set — Gran Cenote includes rental in the fee; others charge extra. Bring your own if you have one.
A rash guard — for extended swimming and sun protection without sunscreen.

Life jackets are available at most cenotes, usually free or for a small fee (20–50 MXN). Take one. Many cenotes look shallow but drop to 30–50m. The cold thermocline is a real thing.

Book Cenote Tours

Viator has a strong selection of guided cenote tours — cave snorkeling, whale shark combination days from Cancún, and full-day multi-cenote routes from Playa del Carmen and Tulum. Guided tours often get you into cave sections that you can’t access independently.

Browse Mexico cenote tours on Viator →

Travel Insurance

Some cenote activities — cave diving, cliff jumping, deep snorkeling — are classified as adventure activities. Standard travel insurance may not cover these. Check your policy before you go, especially if it needs to include water sports or cave-related activities.

Best Cenotes in Mexico: The Listicle — ranked list of the top 20 cenotes across Mexico
Tulum Travel Guide — cenotes, ruins, beach, and where to stay
Valladolid Travel Guide — colonial town with excellent nearby cenotes
Day Trips from Tulum — Dos Ojos, Sian Ka’an, and beyond
Yucatan 7-Day Itinerary — how to combine cenotes with Chichen Itza, Mérida, and the coast