Sargassum, a floating brown seaweed, usually reaches Tulum's beaches between April and October, heaviest from June to August. 2026 was a heavy year: it arrived early and Tulum was still rated Moderate, swimming not recommended, on 19 October. The cenotes are inland fresh water and unaffected, so they are the best fallback.
Sargassum, a brown seaweed that floats in huge mats across the Atlantic, usually reaches Tulum’s beaches between April and October, with the heaviest landings from June to August. In 2026 it came early and stayed late: on 19 October 2026 a tracker still rated Tulum Moderate, with swimming not recommended. The months from November to March are usually the clearest. If the beach is brown on your dates, swim in the cenotes instead: they are inland fresh water, and the seaweed cannot reach them.
Heavy, and early. Riviera Maya News reported on 27 January 2026 that Tulum had already collected 185 tonnes of seaweed that year, which it called an early and constant arrival. Mexico’s navy (SEMAR) said it had collected 123,000 tonnes in Quintana Roo by mid-October 2026, against 92,000 tonnes in the whole of 2025, according to UnoTV on 14 October 2026. Other reports give 2025 a higher total, so we do not call either year a record.
The University of South Florida’s Sargassum Watch, a satellite-based monthly outlook, called 2026 the second-largest year after 2025 in its July bulletin. It expected amounts to keep falling until about November. Its 31 August bulletin found totals falling in every region but still above the 75th percentile of past years, which means more beaching than usual.
| Date | Source | What it said |
|---|---|---|
| 5 and 12 October 2026 | HowIsTheSargassum weekly report | Tulum Moderate |
| 14 October 2026 | UnoTV, citing SEMAR | New landing in Tulum; several points on red and orange alert |
| 19 October 2026 | HowIsTheSargassum weekly report | Moderate, Light to Moderate by beach; swimming not recommended |
| October 2026 | Tulum’s beach department (ZOFEMAT), as reported | Water off Playa Paraíso had cleared; more than 5,600 t collected in Tulum in 2026 |
The tracker and the town disagree, which is normal: conditions change by beach and by day. HowIsTheSargassum is a commercial site that says it uses USF satellite images, beach cameras and local reports. Use it, or Quintana Roo’s colour-coded alerts, on the morning you plan a beach day.
November to March, most years. That lines up with the dry season, when Tulum’s weather is also at its best (see best time to visit Tulum). But the season has no fixed edges. The 2026 landings began in January and were still going in late October, so a winter trip is a better bet, not a guarantee.
Our month guides track what to expect in December, January, February and March.
Floating mats turn the water brown near the shore and pile up on the sand. Once a pile has been on land for about 48 hours it starts to release hydrogen sulphide and ammonia, according to the US Environmental Protection Agency; hydrogen sulphide is the rotten-egg smell. The EPA says breathing these gases can worsen asthma and other breathing problems, so people with those conditions should keep away from rotting piles. In Tulum, the municipal beach department (ZOFEMAT) clears the public beaches, while hotels, the navy and the federal parks agency clear their own stretches.
If you are booking a beach hotel in the Hotel Zone between April and October, check a tracker a week before you go and again the day before. Our Tulum beaches guide lists the public access points.
This is where Tulum has an advantage over most Caribbean resorts. The cenotes are pools of fresh groundwater in the limestone, inland or set back from the sea, so they are clear whatever is happening on the beach. Water temperature is about 24 to 25°C all year.
| Cenote | From Tulum town | Why go on a sargassum day |
|---|---|---|
| Cenote Calavera | 3.3 km | Closest to town; jump holes |
| Gran Cenote | 5 km | Clear water, turtles, cavern snorkelling |
| Cristal and Escondido | 4.8 km | Two open cenotes across the road from each other |
| Zacil-Ha | 9 km | Open pool, with a zip line |
| Casa Tortuga | 14 km | Several cenotes on one ticket, good for families |
| Dos Ojos | 22 km | The big cavern swim |
| Laguna Kaan Luum | 16 km | A shallow inland lagoon around a deep sinkhole |
Casa Cenote is the exception to check. It is a mangrove channel connected underground to the sea, and we found no report on whether sargassum reaches it.
A sargassum week is also a good moment to go inland: the Cobá ruins and the Cobá cenotes are about an hour away, and a Sian Ka’an canal float takes place on inland lagoons and canals. Our Tulum cenote map groups every cenote by road, and cenote entrance fees lists what each one charges.
| Months | Usual pattern | 2026 |
|---|---|---|
| November to March | Usually the clearest months | 185 t collected in Tulum by 27 January |
| April and May | Season usually begins | |
| June to August | Usually the heaviest landings | |
| September and October | Landings continue | Moderate in Tulum on 19 October; new landing on 14 October |
The pattern is a guide, not a forecast. The University of South Florida publishes a monthly outlook for the whole Atlantic belt, and HowIsTheSargassum posts weekly reports for Tulum and other Riviera Maya beaches. Quintana Roo uses a colour-coded alert, with red and orange marking excessive seaweed, which local press reports when beaches change.
Cenote tours on our tours page run in any sargassum conditions.
4 hours
A morning run from central Tulum to Gran Cenote, the jump platforms at Cenote Zemway and the mangrove edge of Casa Cenote, with snorkel gear, towels and transport between stops.
No pickup: meet on site
from$135
Check availability6 hours
A ten-person van tour that reaches Casa Cenote before the crowds, moves on to Taak Bi Ha, and finishes with lamplit snorkeling in a private underground cenote after a vegetarian jungle lunch.
Pickup: Tulum
from$169
Check availability1 day
Entry to the Casa Tortuga cenote park with a 90-minute guided swim through three open and two semi-open cenotes, then free time until closing; higher passes add a zip line and lunch.
No pickup: meet on site
from$26
Check availability6 hours
Young guides from the Chemuyil community lead you on jungle trails to three dark cave cenotes with headlamps and wetsuits, then back to the village for a home-cooked meal.
No pickup: meet on site
from$56
Check availabilityPrices and ratings were taken from GetYourGuide and can change. Booking through these links supports this site at no extra cost to you.
Usually April to October, with the heaviest landings from June to August. Seasons vary a lot from year to year. In 2026 the seaweed arrived early, with 185 tonnes already collected in Tulum by late January, and a tracker still rated Tulum Moderate on 19 October. November to March are usually the clearest months, but check a live report before you book a beach stay.
On 19 October 2026 HowIsTheSargassum rated Tulum Moderate, varying from Light to Moderate by beach, with swimming not recommended. On 14 October UnoTV reported a new landing, with several points on red and orange alert. Tulum's beach department said at one point that the water off Playa Paraíso had cleared. Conditions change daily, so check a live tracker on the day.
No. Cenotes are inland pools of fresh groundwater, so the floating seaweed that washes up on the coast cannot reach them. Gran Cenote, Calavera, Dos Ojos and the rest are unaffected in any season. Casa Cenote is the one to check: it is a mangrove channel connected underground to the sea, and we found no report on whether sargassum ever reaches it.
For most visitors it is unpleasant rather than dangerous. The US Environmental Protection Agency says piles on land start releasing hydrogen sulphide and ammonia after about 48 hours, and breathing these gases can worsen asthma and other breathing problems. Florida's health department says the general public should not be affected in open areas like beaches, but advises people with asthma to limit time near rotting piles.
It shifts with wind and currents, so no beach is reliably clear. Trackers rate beaches separately, and on 19 October 2026 Tulum's beaches ranged from Light to Moderate. The cenotes are fresh water and unaffected, and inland Laguna Kaan Luum is away from the coast. Akumal and the bays north of Tulum are reported separately by trackers, so compare before you drive.
The best time to visit Tulum is December to April, the dry season, with daily highs of 29 to 31°C and the least rain; March is the driest month.
Tulum's beaches fall into two stretches.
Tulum's cenotes sit along three roads.
You can swim and snorkel in most cenotes around Tulum.