An HNL Alert warns swimmers that box jellyfish have been spotted along Oahu’s south-facing shores, including Waikiki and Ala Moana; warning signs are posted. The alert was issued at about 9:45 a.m. Box jellyfish (Phylum Cnidaria) typically appear 8–10 days after a full moon and can deliver painful stings. Check with a lifeguard before entering the water and call 911 in an emergency.
Box Jellyfish Advisory for Oahu’s South-Facing Shores — Waikiki & Ala Moana
An HNL Alert warns swimmers that box jellyfish have been spotted along Oahu’s south-facing shores, including Waikiki and Ala Moana; warning signs are posted. The alert was issued at about 9:45 a.m. Box jellyfish (Phylum Cnidaria) typically appear 8–10 days after a full moon and can deliver painful stings. Check with a lifeguard before entering the water and call 911 in an emergency.
12:33 PM, 11/15/2025Health
Box Jellyfish Advisory Issued for Oahu’s South-Facing Shores
An HNL Alert was issued at about 9:45 a.m. after lifeguards observed box jellyfish along Oahu’s south-facing shores, including popular swimming areas at Waikiki and Ala Moana. Warning signs have been posted at affected beaches.
What you should know: Box jellyfish are members of the invertebrate Phylum Cnidaria and often appear about eight to 10 days after a full moon. Their contact can cause painful stings.
Safety advice: Always check with a lifeguard for the latest beach and ocean conditions before entering the water. If you see jellyfish in the water or washed up on the shore, stay out of the water and keep children and pets away. If someone is stung, seek immediate help from a lifeguard or call 911.
For non-emergency alerts: To receive HNL Alerts, visit hnlalert.gov or text HNLALERT to 888777.
If you want more information about beach safety or the current advisory, ask a lifeguard on duty or check the official HNL Alert resources.