Marine hazards in the Philippines: jellyfish, sea urchins and reefs

Urchin spines and coral cuts are painful and prone to infection, while box jellyfish, stonefish and cone snails can be dangerous: Australia's government health service lists all three, along with sea urchins, among stings that need urgent medical care (healthdirect). Avoid contact, cover up in jellyfish areas, never handle shells or reef animals, and get a person who is stung by anything severe to a hospital while you call 911. Basic first aid helps, but it does not replace medical care.

This guide is general information, not a substitute for first aid training or medical advice. In an emergency, call 911.

Which marine hazards matter most in the Philippines?

We have ordered these by how likely a swimmer or snorkeller is to meet them and how serious they can be, based on judgement rather than data. We searched for a national count of marine injuries in the Philippines and did not find one.

1. Jellyfish, including box jellyfish
2. Sea urchins
3. Coral and reef cuts
4. Stonefish
5. Cone snails

Are there dangerous jellyfish in Philippine waters?

Yes. In 2025 biologists from the University of the Philippines Diliman and partner institutions reported strong evidence that the venomous box jellyfish Chironex yamaguchii, previously known from Japan, lives in Philippine waters (Regional Studies in Marine Science, 2025, as reported by the UP College of Science). The researchers say the Philippine population may be a separate, cryptic species. Press coverage says the specimens came from the central Philippines, six collected in 2016 and 14 in 2019 (Manila Bulletin, 16 February 2025). We have not read the journal paper itself.

A second 2025 paper in Thalassas reported the first confirmed presence in the Philippines of several Irukandji-type jellyfish, small box jellyfish some of which can cause the painful Irukandji syndrome, and new records of Malo filipina and Copula sivickisi. Sites included Batangas, Aurora and Mindoro, including Puerto Galera (Boco et al., Thalassas 41(4):212, 2025, as reported by UP IESM). We have not read the paper itself.

We could not find a systematic public record of jellyfish stings in the Philippines, so we cannot say how common serious cases are. The UP College of Science article notes that the government has no systematic plan for jellyfish, citing a 2022 news article (UP College of Science, 21 February 2025).

How can you avoid jellyfish stings?

• Cover up. The DOH Central Visayas epidemiology unit advises wearing a rash guard or wetsuit as a layer between tentacles and skin. It adds that anti-sting creams may not be effective but are better than nothing if you have no suitable swimwear (SunStar Cebu, 1 July 2023). Australia's healthdirect likewise advises a full-body stinger suit in tropical waters and swimming at patrolled beaches (healthdirect).
• Ask locally. Check with lifeguards, resorts or the barangay about recent jellyfish sightings. The UP researchers suggest avoiding certain areas during peak jellyfish seasons and using protective gear (UP College of Science). We found no source that names which months or locations carry higher risk in the Philippines.

What is the first aid for a jellyfish sting?

Experts disagree on some details, so this section shows who recommends what. Because guidance differs, the safest course after a serious sting is to get the person to hospital and call 911.

Common ground

• Get the person out of the water and back to the beach, and take them to the nearest hospital, especially for a large sting or if they feel unwell (DOH Region 7, as reported by SunStar Cebu, 2023; UP-PGH toxicologist, UP Manila, 2024).
• Do not pour urine on the sting. DOH Region 7 and the UP toxicologist both say not to.
• Do not use fresh or tap water on the sting, because it may trigger more venom release (UP Manila, 2024). An international review panel's draft and the American Red Cross both describe rinsing with sea water (ILCOR draft; American Red Cross Scientific Advisory Council, 2016, which we could not open directly and know from search-result descriptions).
• Call 911 if the person collapses, has trouble breathing or shows signs of a severe allergic reaction. Healthdirect advises calling emergency services and starting CPR if needed after a box jellyfish or Irukandji sting (healthdirect). If the person stops breathing, see First aid and rescue breathing basics.

Where sources differ

• Vinegar. A UP-PGH toxicologist, Dr John David Comandante, said in 2024 that vinegar is the most effective first aid for box jellyfish stings in the Indo-Pacific (UP Manila, July 2024). DOH Region 7 told SunStar Cebu that, per Red Cross Australia, a sting should be rinsed with vinegar for at least 30 seconds (SunStar Cebu, 2023), and healthdirect gives the same step for box jellyfish and Irukandji stings (healthdirect). A peer-reviewed commentary calls vinegar the treatment of choice for box jellyfish stings in Australia while noting the evidence is limited and that one study found vinegar on discharged stinging cells could increase venom release (Seymour, Medical Journal of Australia, 2017). However, the American Red Cross Scientific Advisory Council (2016) no longer recommends vinegar for most jellyfish stings in United States waters, and an international review panel (ILCOR draft for public comment, undated) did not recommend vinegar as a standalone treatment and said it may be unsuitable for some species. We have not found a Philippine Red Cross position. Because experts disagree, do not rely on first aid alone for a suspected box jellyfish sting: get medical help and call 911.
• Hot water. The American Red Cross (2016) describes hot water, as hot as the person can tolerate without scalding (roughly 106 to 113 degrees Fahrenheit, about 41 to 45 degrees Celsius), for up to 20 minutes or until pain eases. The ILCOR draft suggests warm water at 40 to 45 degrees Celsius over cold packs for pain relief, rating the evidence very low certainty. The UP toxicologist also suggests hot water for pain.
• Removing tentacles. UP Manila says use a stick or tweezers, not bare hands. DOH Region 7 (via SunStar Cebu) mentions tweezers, the American Red Cross describes lifting or scraping with a blunt object, and healthdirect says to pick tentacles off.
• Pressure bandages. Pressure immobilisation bandages were removed from Australian guidelines for jellyfish after studies suggested they increase venom release (Seymour, 2017). They are described for cone shell stings (below), not jellyfish stings.

Alcohol, ammonia and rubbing with sand are not advised. The ILCOR draft recommends against 10% ammonia, isopropanol and ethanol on jellyfish stings; the UP toxicologist also advises against rubbing with sand and applying alcohol (UP Manila).

What happens if you step on a sea urchin?

Sea urchin spines can break off in the skin and are painful. The Divers Alert Network (DAN) advises:

• Soak the area in hot water, no hotter than 45 degrees Celsius (113 degrees Fahrenheit), for 30 to 90 minutes, repeating if needed. Test the water on yourself first, because pain can make it hard to judge the temperature.
• Remove superficial spines with tweezers or bare fingers; they are hollow and fragile. Leave deeply embedded spines for a medical professional.
• Wash the area gently, avoiding hard scrubbing if spines may remain.
• Do not close the wound with tape or glue.
• Get a professional evaluation as soon as reasonably possible, even after first aid. (DAN, Sea Urchins, accessed 12 October 2026.) Healthdirect also lists sea urchin stings among those needing urgent care (healthdirect).

DAN is a diving-medicine organisation, not a Philippine health authority. Prevention: watch your footing over rocky bottoms, keep your distance and control your buoyancy near rocks and wrecks, and do not handle urchins (DAN).

How do you treat a coral cut?

Coral is covered in living tissue that can be left in a scrape. DAN advises scrubbing the cut vigorously with soap and water, flushing with large amounts of water, applying a thin layer of antiseptic ointment, covering with a dry, sterile, non-stick dressing, and cleaning and redressing it twice a day. See a doctor if there is extreme redness, red streaks spreading from the wound, pain, fever, pus or swollen lymph glands. A possible Vibrio infection can cause serious illness in people with impaired immune systems, for example from diabetes or chronic liver disease (DAN, Coral Scrapes and Cuts, accessed 12 October 2026). DAN is not a Philippine health authority.

Prevention: do not touch or stand on coral. This also protects the reef. DAN recommends a wetsuit or dive skin to protect against being pushed into coral by a current (DAN).

What about stonefish?

Stonefish are well-camouflaged reef fish with venomous spines on the back. A 2021 review by James Cook University researchers reports confirmed sightings of the estuarine stonefish (Synanceia horrida) in the Philippines, as well as Malaysia, Indonesia, Singapore, Thailand and northern Australia (Saggiomo and colleagues, Marine Drugs, 2021, as listed by James Cook University; we could not open the full text, so this is from a search-result description).

A stonefish sting needs urgent medical care. Call 911 and get the person to a hospital. Australian sources describe soaking the stung area in hot water, no hotter than can be easily tolerated, for pain. Healthdirect says up to 30 minutes (healthdirect); St John Ambulance WA gives no duration (St John Ambulance WA). Laboratory work at James Cook University found S. horrida venom is heat-sensitive, which is the rationale for hot-water immersion (Barnett, Saggiomo, Smout and Seymour, Diving and Hyperbaric Medicine 47(3), 2017, JCU). Pressure bandages are not used for stonefish (NSW Poisons Information Centre). A Hong Kong case report describes serious infections in two patients who were bathed in hot water after stonefish stings, which is another reason to get medical care (Hong Kong Medical Journal, as listed in search results).

Where sources differ: on spines left in the skin, healthdirect says to leave the spine in place unless the ambulance operator says otherwise, while St John Ambulance WA says to carefully remove remaining spines from a limb. Ask the emergency operator what to do.

Prevention: watch where you step over rocky or reefy bottoms, as DAN advises for sea urchins (DAN). Healthdirect advises shuffling your feet when entering the water to reduce stingray injuries (healthdirect). We did not find a source that gives shuffling advice for stonefish specifically.

Why should you never pick up a cone snail?

All roughly 600 species of cone snails are venomous, according to DAN. They live mainly in tropical and subtropical waters, often partly hidden under sand, rock or coral on shallow reefs. DAN says there is no specific treatment for cone snail stings, so anyone stung needs medical evaluation (DAN, Cone Snails, accessed 12 October 2026). The science outlet FlipScience says the geography cone (Conus geographus) can be found on many Philippine reefs and that its venom has proven fatal to humans (FlipScience). Do not touch any cone-shaped shell; the animal can hide inside.

If someone is stung, call 911 and get them to emergency care. Do not wait for symptoms: healthdirect lists cone snail stings among those needing urgent care (healthdirect). DAN, healthdirect and the NSW Poisons Information Centre all describe a pressure immobilisation bandage for cone shell stings: a firm, wide elasticated bandage along the whole limb, keeping the person calm and still, and giving CPR if needed (DAN; healthdirect; NSW Poisons Information Centre). This is a different technique from the advice for jellyfish and stonefish, and the sources are Australian and American, so follow the 911 operator's instructions where they differ.

When should you call 911 or go to hospital?

Go to hospital immediately, calling 911 on the way if possible, if:

• the person has trouble breathing, collapses, becomes confused or feels very unwell;
• signs of a severe allergic reaction appear, such as swelling of the face or throat;
• the sting is from a box jellyfish, stonefish, sea urchin or cone snail, or the injured area is large;
• a wound shows signs of infection (spreading redness, pus, fever).

This list follows healthdirect (call emergency services for breathing trouble, collapse or suspected anaphylaxis; urgent care after box jellyfish, stonefish, sea urchin and cone snail stings) and DAN (infection signs). We could not find equivalent Philippine Red Cross or DOH national marine first aid text.

Next steps

Read more about Where and how drownings happen in the Philippines, Rip currents and how to escape them and Typhoons, storm surge and flash floods, or return to the Basics & Risks hub. For first aid skills, consider a certified course. The Philippine Red Cross lists first aid and CPR courses on its training page, and the Philippine Life Saving Society runs first aid and water safety training through its chapters (for example, a 2024 course with the University of Baguio). We could not find a current public course schedule for either, so contact them directly.

Sources

1. University of the Philippines College of Science (21 February 2025). "Venomous jellyfish found in PH waters, biologists confirm." https://science.upd.edu.ph/venomous-jellyfish-found-in-ph-waters-biologists-confirm/ (reporting Boco et al., Regional Studies in Marine Science, 2025; journal paper not opened)
2. Manila Bulletin (16 February 2025). "Study confirms presence of deadly box jellyfish in the Philippines' Coral Triangle region." https://mb.com.ph/2025/02/16/study-confirms-presence-of-deadly-box-jellyfish-in-the-philippines-coral-triangle-region (as described in search results; page not opened)
3. UP Institute of Environmental Science and Meteorology (22 December 2025). "Philippine box jellyfish: new and first records discovered in the Coral Triangle." https://iesm.science.upd.edu.ph/philippine-box-jellyfish-new-and-first-records-discovered-in-the-coral-triangle/ (reporting Boco et al., Thalassas 41(4):212, 2025, DOI 10.1007/s41208-025-00970-9; paper not opened)
4. SunStar Cebu (1 July 2023). "DOH warns against jellyfish stings" (DOH Region 7 epidemiology surveillance unit). https://www.sunstar.com.ph/cebu/local-news/doh-warns-against-jellyfish-stings
5. University of the Philippines Manila (2 July 2024). "Celebrating UP-PGH National Poison Prevention Week: insights on venoms, common poisons and first aid tips." https://www.upm.edu.ph/cpt_news/celebrating-up-pgh-national-poison-prevention-week-insights-on-venoms-common-poisons-and-first-aid-tips/
6. Seymour JE (2017). Are we using the correct first aid for jellyfish? Medical Journal of Australia 206(6):249-250. https://www.mja.com.au/journal/2017/206/6/are-we-using-correct-first-aid-jellyfish
7. International Liaison Committee on Resuscitation (ILCOR). Treatment of jellyfish stings (draft for public comment, undated). https://costr.ilcor.org/document/treatment-of-jellyfish-stings-fa-7211-tf-sr
8. American Red Cross Scientific Advisory Council (June 2016). Advisory: Jellyfish stings. https://redcross.org/content/dam/redcross/Health-Safety-Services/scientific-advisory-council/Scientific%20Advisory%20Council%20ADVISORY%20-%20Jellyfish%20Stings.pdf (direct access was blocked; content known from search-result descriptions)
9. Divers Alert Network (DAN). Sea Urchins. https://dan.org/health-medicine/health-resources/diseases-conditions/sea-urchins/ (accessed 12 October 2026; undated)
10. Divers Alert Network (DAN). Coral Scrapes and Cuts. https://dan.org/health-medicine/health-resources/diseases-conditions/coral-scrapes-cuts/ (accessed 12 October 2026; undated)
11. Divers Alert Network (DAN). Cone Snails. https://dan.org/health-medicine/health-resources/diseases-conditions/cone-snails/ (accessed 12 October 2026; undated)
12. healthdirect (Australian Government). Sea creature stings. https://www.healthdirect.gov.au/sea-creature-stings (accessed 12 October 2026; undated)
13. St John Ambulance WA. First aid fact sheet: marine stings. https://www.stjohnwa.com.au/online-resources/first-aid-information-and-resources/marine-stings (accessed 2026; no date shown)
14. NSW Poisons Information Centre. First aid. https://www.poisonsinfo.nsw.gov.au/First-Aid.aspx (accessed 12 October 2026; undated)
15. Barnett S, Saggiomo S, Smout M, Seymour J (2017). Heat deactivation of the stonefish Synanceia horrida venom: implications for first-aid management. Diving and Hyperbaric Medicine 47(3):155-158. https://researchonline.jcu.edu.au/50150/
16. Saggiomo and colleagues (2021). The geographic distribution, venom components, pathology and treatments of stonefish (Synanceia spp.) venom. Marine Drugs. https://portfolio.jcu.edu.au/publications/JCU172018 (known from a search-result description; full text not opened)
17. Hong Kong Medical Journal. Case report on necrotising fasciitis after stonefish sting and hot-water bathing. https://www.hkmj.org/system/files/hkm0912p471.pdf (known from a search-result description; year and authors not confirmed)
18. FlipScience. "Geography cone snail." https://www.flipscience.ph/flipfacts/geography-cone-snail/ (popular science outlet; no date seen)
19. Philippine Red Cross. Trainings. https://redcross.org.ph/trainings (course listing only)
20. University of Baguio (13 December 2024). "University of Baguio empowers future professionals with life-saving skills." https://scjps.ubaguio.edu/university-of-baguio-empowers-future-professionals-with-life-saving-skills/ (example of Philippine Life Saving Society training)

Last reviewed: 12 October 2026.