Sargassum in Akumal — Season, What to Expect and Where the Water Stays Clear

Sargassum is a floating brown seaweed. It drifts across the Atlantic and the Caribbean in large mats and, depending on winds and currents, some of it washes onto the Caribbean coast of Mexico. When it arrives in volume it can turn the water brownish near the shore and pile up on the sand.

It is not a pollution spill and it is not new, but in the last years the amounts have grown. The University of South Florida's Optical Oceanography Lab tracks it by satellite and publishes monthly outlooks for the Caribbean.

It is also very uneven: one beach can be covered while the next one is clean, and the picture can change from morning to afternoon.

There is no fixed calendar. As a general guide, the Mexican Caribbean sargassum season runs from about April to October, with the heaviest period usually between May and August and June–July often the peak. Collection work normally winds down in early November.

Recent years show how much it can vary. In 2025, the Quintana Roo government declared the season closed with about 91,500 tonnes collected by 31 October. In 2026 it started much earlier: it was already washing ashore in January, peaked around June and July, and the state recorded a record of about 138,000 tonnes collected by October.

On 8 October 2026 the Mexican Navy reported a very low level (green) for the Caribbean, and the trend was downward after the summer peak. That is a snapshot, not a promise for your dates.

• January–March: usually low, but 2026 showed it can start early.
• April: the season usually begins.
• May–August: the typical peak, especially June and July.
• September–October: usually decreasing, with ups and downs.
• November–December: normally minimal.

Akumal Bay faces the Caribbean, so on some days sargassum can reach the shore or float in the water, as on other beaches of the Riviera Maya. How much depends on the day, the wind and the current. We cannot promise clear water, and we will not tell you the sea is always perfect.

On a good day the bay is clear and calm and you swim among seagrass and turtles. On a bad day there can be floating weed or brownish water, and visibility is lower. The turtles live in the bay all year, but sightings are never guaranteed, and a day with a lot of weed can make it harder.

The quickest way to know is to check the day before and the morning of your tour (next section) and to write to us. We are on the water every day and we tell you what we actually see.

Cenotes: they are freshwater sinkholes inland, and sargassum is a floating ocean seaweed. It does not grow in them or drift into them. If you want a day with no sea at all, our 3-cenote tour has no ocean section.

Yal-Kú Lagoon: it is a protected inlet with mangroves, rocks and seagrass beside the bay. We do not have a verified source about how sargassum affects it, so we do not claim it is always free of it. We tell you what the lagoon looks like on the day, if you write to us.

Careful with combos: the turtles + Cenote Dos Ojos + Bat Cave tour includes 1 hour in Akumal Bay together with the cenote visit, so the sea part still depends on the day.

There is no single perfect source, but these are the ones used in Quintana Roo reports:

• Beach traffic light (semáforo): green means low or none, yellow moderate, orange abundant and red excessive. The state environment ministry (SEMA) monitors around 140 beaches, and the Red de Monitoreo del Sargazo de Quintana Roo publishes daily maps, mostly on its social media (search for its name).
• Secretaría de Marina: publishes a general level and traffic light for the Mexican Caribbean. It is a regional number, not a report for one beach.
• Satellite outlooks: the University of South Florida publishes monthly bulletins at optics.marine.usf.edu. They estimate risk, but do not replace looking at the actual beach.
• Us: message us on WhatsApp the day before or that morning. We see the bay every day.

Everything is booked and paid online, and you get free cancellation up to 24 hours before your tour. If you are worried about the sea, check the status 24 hours before and write to us on WhatsApp so we can tell you what we see and look at options together.

We confirm your exact time by email after you book. For changes within less than 24 hours, write to us on WhatsApp; we will tell you what is possible, but the free-cancellation rule is the 24-hour one.

You will not hear from us "the water is always perfect". You will hear what the sea looks like.

• Travelling in May–August? Allow flexible days, and book the tour for a day when you can move it if needed.
• Check the status the day before and again that morning.
• Cenote days are a good plan B when the sea is weedy.
• Read our best time to snorkel in Akumal and the snorkeling guide for the rest of the year.
• Remember: no sunscreen in the water; a UV shirt works well.