Cancun's busiest travel period is underway (late Dec.-March), and travelers expecting crystal-clear Caribbean waters have been shocked over the past week as seaweed piled up to shin-high levels in some of the prime hotel and resort areas.

"Travelers who booked a January 2026 trip to the Riviera Maya expecting guaranteed crystal-clear water were hit with a rude awakening this week," local outlet Cancun Sun said.

In recent weeks, an "atypical surge" of sargassum seaweed hit the coast and covered some of the resort town's most popular beaches...

Cancun Sun reported, citing a University of South Florida study that tracks blooms and warns that the "sargassum-free season" is disappearing.

Sargassum Monitoring Mapping Network

Report continues:

Here is what we know, and why 2026 is acting so differently.

The "Winter Die-Off" Failed. Usually, sargassum is a seasonal problem. The massive "seed population" of algae floating in the Atlantic typically blooms in the spring and dies off when the water cools in November and December.

That didn’t happen this year.

According to USF data, the bloom remained historically strong through late 2025. Instead of withering away in the cooler temperatures, the biomass survived and continued to grow.

The result? The "season" didn't end; it just paused. And now, that massive surplus of seaweed is arriving on our shores months ahead of schedule. As we detailed in our 2026 Sargassum Outlook, early arrivals like this are often a warning sign of a "major" year to come.

With algorithms routing consumers to top resort destinations, you might want to think twice about Cancun at the moment. But not all is lost. There is still Coco Bongo.