Waikiki Beach is located in the capital city of Honolulu, Hawaii on the island of Oahu. Millions of visitors are attracted to Waikiki each year for its beautiful beaches and clear blue waters, shops, and island attractions.
Waikiki stretches for two miles along the southern coast of Oahu and is split up into sections, consisting of more than five different beaches.
Located in the North Pacific Ocean, Waikiki is surrounded by several bodies of water, including Kahanamoku Lagoon, Magic Island Lagoon, Grays Channel, and Waikīkī Bay. As a tourist attraction hotspot, Waikiki has a plethora of hotels, resorts, and restaurants along the beachside.
If you’re planning on visiting Waikiki (or maybe you’re already there!) you might be wondering:
Does Waikiki have jellyfish? Is it safe to swim at Waikiki beach?
Jellyfish are a common sea creature that inhabit the waters surrounding the Hawaiian islands, including Oahu. The most common jellyfish species observed in Waikiki waters include:
- Box jellyfish
- Moon jellyfish
- White-spotted jellyfish
Stings from box jellyfish, in particular, can be common during jellyfish invasions — typically occuring shortly after a full moon. Check the Waikiki Aquarium jellyfish calendar if you want to avoid these painful but non-lethal stings.
Let’s take a look at the types of jellyfish species you may encounter while in Waikiki and common times these jellyfish like to pop up on Waikiki Beach shores!
Types of Jellyfish at Waikiki, HI
Waikiki Beach is one of the most common areas on the island of Oahu that experiences jellyfish invasions following a full moon.
Although there are jellyfish species that can give life-threatening stings to humans, jellyfish that frequent Hawaiian waters are not known to be deadly. They do, however, have the ability to deliver powerful stings that can be very painful.
The box jellyfish is the most common jellyfish species seen in Hawaiian waters compared to the moon and white-spotted jellyfish. Waikiki has been known to have box jellyfish invasions, which has resulted in beach goers being stung.
There are two other sea creatures in Waikiki waters that highly resemble the jellyfish, but they are not classified as such. These species include the Portuguese man o’ war and sea lice.
Let’s dive into the characteristics and interesting facts of common jellyfish species in Waikiki and those alike!
Box Jellyfish
Box jellyfish belong to the Carybdeidae family. Waikiki is home to three different box jellyfish species within this family, including Carybdea alata, Carybdea rastoni (jimble jellyfish), and Carybdea Sivickisi C. alata (winged box jellyfish).
The box jellyfish that inhabit Hawaiian waters are relatively small, with the largest of the three being the winged box jellyfish measuring up to 3 inches (7.6 cm) tall and 2 inches (5 cm) in diameter.
Waikiki box jellyfish have a transparent body with four stinging tentacles attached. These jellies possess sensory structures below their body within the stinging tentacles that serve as an organ and light detector.
Box jellyfish prefer to inhabit calm, shallow tropical waters, which attracts them to the bays and estuaries in Waikiki. Box jellies can deliver a painful sting, which is executed by releasing a toxin from the stinging cells on their tentacles. There have been cases of box jellyfish swarms, also referred to as invasions, in Waikiki waters.
Although box jelly stings are very painful, box jellyfish in Hawaii are not deadly to humans, excluding severe allergic reactions.
Moon Jellyfish
Moon jellyfish are fairly large transparent jellies that can range from 12 to 24 inches (30-60 cm) in diameter. Moon jellyfish possess several tentacles that are almost unidentifiable upon first glance because they are very short and fine.
Moon jellyfish do not deliver a powerful sting and if you were to be stung by one, the pain would be mild to almost nonexistent.
Moon jellyfish aren’t very effective swimmers, so they do not purposefully travel close to shore. Due to their lack of swimming abilities, moon jellyfish are carried by the ocean’s tides close to shore where they often get trapped until the current is able to carry them out to sea again.
Waikiki may attract moon jellyfish due to high levels of human activity in the area.
According to the ocean conservation organization Oceana, moon jellyfish are believed to favor habitats with high human activity to avoid predators and decrease competition over food sources.
White-spotted Jellyfish
White-spotted jellyfish inhabit the various bodies of water off the island of Oahu, including bays and lagoons in Waikiki. Because of their preference to live in bays and lagoons, these jellyfish were given the nickname “lagoon jelly”.
The white-spotted jellyfish is considered an invasive species in Hawaiian waters because they are native to Australia. Due to their constant feeding habits, white-spotted jellyfish can deplete zooplankton populations that other native sea creatures feed on.
The body of a white-spotted jellyfish can range from 4 to 12 inches (10-30 cm) in diameter and is decorated with white specks, giving this species its name. White-spotted jellyfish possess eight thick tentacles that have the ability to sting their prey for capture.
Despite their intimidatingly large tentacles, white-spotted jellyfish do not pose a threat to humans. Their sting produces a venom that is non-toxic to humans, typically resulting in only a mild reaction, if any at all.
The most common bodies of water that white-spotted jellyfish frequent on the island of Oahu include the Ala Wai Canal, Pearl Harbor, Honolulu Harbor, and Kaneohe Bay. The Ala Wai Canal is fed by the Kahanamoku Lagoon, located in the northwestern portion of Waikiki. White-spotted jellyfish may also appear along the shores of Waikīkī Bay.
Portuguese Man O’ War
Although the Portuguese man o’ war is not a part of the jellyfish species, it should be included in this list because of its uncanny resemblance to the jellyfish.
This sea creature is actually considered a siphonophore, which consists of a colony of organisms known as zooids that function as one. The organisms that make up the Portuguese man o’ war cannot operate independently without each other.
Portuguese men-of-war appear in tropical and temperate waters across the globe. These sea creatures pop up on the shores of Waikiki due to ocean currents and wind because they are unable to swim.
Portuguese men-of-war have a very distinct appearance. They possess a transparent body that acts as a float to carry them across the surface of the sea, which is colored with bluish-purple hues. The tentacles of a Portuguese man o’ war can grow to be extremely long, reaching lengths up to 165 feet (50 m).
Stings by a Portuguese man o’ war can cause excruciating pain for humans.
However, fatal reactions to the sting are a very rare occurrence.
Sea Lice
Although the name can sound misleading, sea lice are small jellyfish larvae.
Before jellyfish mature into adults, they go through a larva stage. Sea lice are commonly reported in coastal waters of the Caribbean, Gulf of Mexico, South America, and U.S. With that said, sea lice are not very common in Hawaiian waters, with very few reports of sea lice irritation.
During the larva stage, tiny jellyfish larvae still have the ability to sting humans when they are threatened.
The stings are not fatal, but they can cause a skin reaction.
Sea lice feel threatened when they are trapped in tight clothing or under hair.
When sea lice sting humans, the reaction typically doesn’t take place until a few hours after the stinging occurs.
Sea lice stings typically result in a noticeable red rash with bumps accompanied by irritation and itching. Sea lice are so small that you can’t really see them in the water, so you will only know if you were stung hours after when a rash appears.
Jellyfish Season & Jellyfish Stings in Waikiki
Jellyfish frequent Hawaiian waters year-round because their activity revolves around tidal patterns and moon cycles.
Box jellyfish invasions are a monthly occurrence, rather than seasonal, as they appear close to the shore approximately 8 to 10 days after a full moon.
Jellyfish reproduction takes place a couple of days after a full moon occurs and when high tide is in play. They appear close to shore afterwards because they get trapped in the shallow waters after the high tide recedes into low tide.
According to Stanford Medicine, approximately 150 million people are stung by jellyfish every year worldwide.
Most jellyfish species in North American waters do not produce a life-threatening sting, excluding allergic reactions, but they can be very painful depending on the species. Jellyfish numbers can differ greatly between hundreds and thousands during an invasion.
Therefore, it is hard to pinpoint an average number of stings in Waikiki annually.
During the event of a jellyfish invasion, jellyfish stings are a fairly common occurrence. In May 2019, more than 900 beach goers in Waikiki got stung by a substantial box jellyfish influx.
Over 5,000 box jellyfish were counted by lifeguards in the area. Additionally, almost 50 other individuals were stung at Hanauma Bay west of Waikiki and Ala Moana Beach in Honolulu.
In late March 2022, Hanauma Bay was shut down due to a large jellyfish invasion that appeared near the shore in the early morning.
Hawaii local news reported that several beach goers were stung, but they were unable to identify the exact number of individuals.
If you want to avoid a jellyfish invasion while in Waikiki, the Waikiki Aquarium provides a calendar for every year. The calendar includes details of when a full moon will take place and the most probable dates for box jellyfish invasions to occur.
Wrapping Up
Although there are a few jellyfish species that live in Hawaiian waters, the box jellyfish is the most well known species to frequent waters surrounding Waikiki.
Jellyfish invasions are very common in Waikiki waters approximately 8 to 10 days after a full moon.
The box jellyfish and Portuguese man o’ war are of most concern if encountered because of the highly painful stings they deliver.
The moon and white-spotted jellyfish are of least concern, as they are less common in Waikiki and do not produce powerful stings that cause a lot of pain.
Sea lice can be unavoidable, but there are very few accounts of beach goers exhibiting sea lice rashes while visiting Waikiki Beach.
As long as you follow the jellyfish calendar to avoid a box jellyfish invasion and are aware of your surroundings in the water, you can enjoy your trip to Waikiki without having to worry about being stung by a jellyfish.
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Hope this helps!