Quick Answer: Box jellyfish are more likely to reach Hawaiʻi’s south and leeward shores about 8 to 10 days after the full moon. Use the current watch windows below to identify times when extra awareness may be helpful, then make swimming and snorkeling decisions based on that day’s local conditions.
Planning aid, not a Maui forecast. These dates come from the Waikīkī Aquarium’s Oʻahu-based calendar and do not predict conditions at a specific Maui beach. A listed date does not confirm that box jellyfish will be present, and an unlisted date does not mean a beach is jellyfish-free.
Before entering the water, check current Maui beach conditions, obey posted signs, and ask a lifeguard when one is present. Stay out of the water if jellyfish have been sighted.
Calendar dates and source links last verified August 7, 2026. This verification does not confirm current beach conditions.
Key Planning Notes:
Calendar dates are only a planning aid. Before entering the water, check current local conditions and speak with a lifeguard when one is present.
These resources report different types of ocean and beach conditions. None should be treated as a guaranteed live box jellyfish tracker.
Planning a snorkel trip to Maui in 2026-2027? One of the most common questions travelers ask is: “When are box jellyfish in Maui?”
This guide breaks down the 2026-2027 high-probability dates, explains why they appear after the full moon, and, most importantly, what it actually means for snorkeling in Maui. Read ahead for more information on the Maui box jellyfish.
| Month | High-probability dates |
|---|---|
| January 2026 | January 11-13 |
| February 2026 | February 9-11 |
| March 2026 | March 11-13 |
| April 2026 | April 9-11 |
| May 2026 | May 9-11 |
| June 2026 | June 7-9 |
| July 2026 | July 7-9 |
| August 2026 | August 6-8 |
| September 2026 | September 4-6 |
| October 2026 | October 4-6 |
| November 2026 | November 2-4 |
| December 2026 | December 2-4 and December 31, 2026-January 2, 2027 |
Source: Waikīkī Aquarium 2026 Box Jellyfish Calendar . These Waikīkī-based dates are planning aids for Maui, not confirmed Maui sightings or guarantees.
| Month | High-probability dates |
|---|---|
| January 2027 | December 31, 2026-January 2, 2027 and January 30-February 1 |
| February 2027 | February 28-March 2 |
| March 2027 | March 30-April 1 |
| April 2027 | April 28-30 |
| May 2027 | May 28-30 |
| June 2027 | June 26-28 |
| July 2027 | July 26-28 |
| August 2027 | August 24-26 |
| September 2027 | September 23-25 |
| October 2027 | October 23-25 |
| November 2027 | November 21-23 |
| December 2027 | December 21-23 |
Source: Waikīkī Aquarium 2027 Box Jellyfish Calendar . These Waikīkī-based dates are planning aids for Maui, not confirmed Maui sightings or guarantees.
If your trip falls during a higher-probability window, a guided boat tour can help reduce uncertainty. Crews monitor daily conditions and choose the safest, clearest available snorkel locations.
👉 Book A Maui Snorkeling Tour And Let The Experts Handle The Conditions
The timing isn’t random.
Research and long-term observation in Hawaiʻi show that box jellyfish tend to appear about 8-10 days after the full moon. University of Hawaiʻi researchers have studied this lunar timing and found it relates to a predictable “darkness window” that cues Hawaiian box jellyfish to migrate shoreward to spawn.
This recurring lunar pattern can help identify times for added awareness, but the calendar does not predict conditions at a specific Maui beach.
However:
That’s why lifeguard guidance and beach warnings always take priority over any calendar. View below the Maui box jellyfish predictions.
Box jellyfish are more commonly reported along south and leeward shores.
On Maui, that can include:
They are less frequently reported on exposed north shores during trade wind conditions, but ocean dynamics change daily.
If you’re shore snorkeling in South Maui:
To find lifeguarded beaches on Maui (towers and hours), use Hawaiʻi Ocean Safety’s official list.
If you’re booking a guided snorkel tour, crews evaluate:
That flexibility often allows tours to operate safely, even during jellyfish windows, by choosing the most suitable location.
Here’s the practical takeaway:
Most visitors snorkel in Maui year-round without incident.
During high-probability windows:
For day‑of updates at lifeguarded beaches (hazard ratings and alerts), check HawaiiBeachSafety.com and still confirm with a lifeguard on arrival.
And remember: jellyfish are a natural part of Hawaiʻi’s ocean ecosystem. Awareness is smart, but panic is unnecessary.
If you want to understand how to evaluate ocean safety in general, check out our Maui Snorkel Conditions 101 guide for wind, waves, and hazard tips.
If you suspect a box jellyfish sting:
Note: University of Hawaiʻi researchers have shown that some commonly recommended “home” treatments can worsen certain box jellyfish stings. When in doubt, get help from a lifeguard. Severe reactions are uncommon, but some stings can be painful and require evaluation.
When in doubt, get help from trained professionals.
It’s important to understand:
Awareness + flexibility = smart planning.
Box jellyfish are more likely to reach Hawaiʻi’s south and leeward shores about 8 to 10 days after the full moon. Use the 2026 and 2027 watch-window tables above for the exact dates shown on the Waikīkī Aquarium calendars. These dates are planning aids for Maui, not a forecast for a specific beach.
No, treat it as a planning tool, not a promise. Waikīkī Aquarium notes that the calendar is informational and jellyfish can appear outside the predicted windows. Read the explanation here: Waikīkī Aquarium Box Jellyfish Calendar. Always follow posted warnings and check with a lifeguard.
Box jellyfish reports are more common along south and leeward shores. On Maui, that means you should watch Kīhei, Wailea, Mākena, and other leeward-facing beaches more closely during higher-probability windows. Conditions can change with currents, wind, and surf, so don't rely on the calendar alone.
The Waikīkī Aquarium calendars generally highlight three-day higher-probability windows, but actual activity can vary. Treat each window as a time for added awareness, not as a fixed start and end time. Jellyfish may appear before or after the listed dates, or not at all.
Understanding the Maui box jellyfish watch windows can help you plan, but current conditions, posted warnings, and lifeguard guidance should determine whether you enter the water.
If you’d rather let experienced captains choose the day’s best conditions:
👉 Reserve Your Maui Snorkeling Tour Today And Let Us Monitor The Ocean For You
Sources & Updates: Before you swim or snorkel, confirm current jellyfish timing, beach warnings, water quality, and ocean conditions using the official resources below.
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