Is there seaweed at your beach? Check sargassum risk by destination and month — instantly.
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SafetyWing travel insurance for Mexico
Sargassum is a type of free-floating brown seaweed that naturally blooms in the open Atlantic and Caribbean. Since around 2011, unusually large blooms have been washing ashore on Caribbean beaches, particularly in summer. The seaweed is harmless but smells of hydrogen sulfide as it decomposes on shore — and can cover beaches entirely during peak months.
Beach orientation is the biggest factor. Beaches facing southeast (like Tulum) are directly exposed to sargassum traveling north through the Caribbean. Beaches facing west or northwest (like Cozumel's west coast, Holbox, and Cancun's Hotel Zone North) are shielded by geography. Coral reef systems like the one protecting Puerto Morelos also reduce how much seaweed reaches the shore.
Pacific coast beaches (Puerto Vallarta, Los Cabos, Oaxaca's coast) and freshwater destinations (Bacalar) have zero sargassum risk — sargassum only comes from the Caribbean/Atlantic.
Cancun Hotel Zone North faces northwest and has very low risk January–March and November–December, moderate May–September. The Hotel Zone South faces east and sees more, particularly June–September. Hotels work hard to clear beaches but can't prevent it completely in peak months.
June through September is peak sargassum season. July and August are usually the worst months. Tulum, facing southeast, is the most exposed major destination on the coast.
Pacific coast beaches (Puerto Vallarta, Los Cabos, Mazatlán, Oaxaca's coast), the Gulf-facing Holbox, and Isla Mujeres Playa Norte all have very low to zero sargassum risk. Bacalar is a freshwater lagoon — completely immune. Cozumel's west coast stays very low year-round thanks to the island blocking Caribbean currents.
Tulum is the highest-risk major destination on the Mexican Caribbean. Its beaches face southeast into the open Caribbean, and risk is very high from April through October. Plan cenote days when the beach is bad — Tulum has exceptional cenotes within 20 minutes of the beach zone.
No. Holbox faces north into the Gulf of Mexico, not the Caribbean. Sargassum originates in the Atlantic and Caribbean and does not significantly reach Gulf-facing beaches. Holbox stays very low all year.
Risk levels are based on historical sargassum data and beach orientation. Actual conditions vary year to year depending on ocean currents and bloom intensity. Always check real-time beach reports closer to your travel date at sargazo.mx or the Caribbean Sargassum Network.