Sand fleas, the little hoppers on the beach, are crustaceans and do not bite. The itchy bites people blame on them usually come from tiny biting midges, which US beachgoers often call sand flies or no-see-ums, mostly at dawn and dusk near water. Entomologists use the name "sand fly" for a different insect again.
Below, we sort out the names, show who is who in one table, and share a simple plan for staying on the sand through sunset.
Sand flies and sand fleas: the short answer
Two beach names cover at least three different animals:
- Sand fleas are beach hoppers. Orkin and Terminix describe them as small jumping crustaceans in the family Talitridae, not fleas and not insects. They don't bite.
- Sand flies, in everyday US beach talk, are usually biting midges. The University of Arizona Extension says no-see-ums "are also known as punkies or sand flies." Female midges do bite.
- Sand flies, in the textbook sense, are phlebotomine sand flies, tiny mothlike flies found mostly in tropical and subtropical regions (Merck Veterinary Manual).
So if something nipped your ankles on an evening beach walk, the hoppers are almost certainly innocent.
What are sand flies?
The name means different insects depending on who is talking.
The beach meaning: biting midges
Most people in the US mean biting midges (genus Culicoides, family Ceratopogonidae). Clemson Extension puts it plainly: "Biting gnats, also called sand gnats or no-see-ums, are in fact biting midges." Up close they look like miniature mosquitoes, and only adult females need blood (University of Arizona Extension).
University of Florida entomologists add that "Biting midges are sometimes incorrectly referred to as sand flies," since true sand flies are a different group. Florida alone has 47 species of biting midges. Our guide to what no-see-ums are has the full profile, and our post on which gnats bite separates them from harmless gnats.
The textbook meaning: phlebotomine sand flies
Entomologists reserve "sand fly" for phlebotomine sand flies (family Psychodidae). The Merck Veterinary Manual says they "are confined primarily to the tropical and subtropical regions of the world." They are tiny, mothlike and covered in fine hairs, also called moth flies or owl midges. The ECDC describes large black eyes, long stilt-like legs and hairy wings held at an angle over the body at rest. Females feed on blood.
A note for Australia
In Australia, "sandflies" usually means biting midges too. Our post on sandflies in Australia covers the local vocabulary.
What are sand fleas?
Sand fleas are beach hoppers, also called beach fleas or sand hoppers. KQED's Deep Look sums it up: "You might know them as sand fleas, but they don't bite and they aren't fleas. They're called beach hoppers."
- Size: about 1/4 inch (Orkin); around 1/4 inch to 1 inch (Terminix). KQED says anywhere from ant size to cricket size.
- Look: gray, brown or tan like the sand, with several pairs of legs and long, thick antennae (Orkin).
- Where: US coastal beaches near the high-tide mark, most numerous where seaweed washes up (Orkin). Terminix notes species on the Atlantic, Gulf and Pacific coasts, including the Gulf sand hopper found along the Gulf coast.
- When: buried by day, out at sunset to feed on beach wrack (washed-up seaweed, especially kelp), back in burrows about a foot deep by sunrise (KQED).
The fun part: a beach hopper "can jump as high as your knees," says KQED. By breaking down seaweed, hoppers return nutrients to the food chain. "Without these hungry acrobats, beaches the world over would be strewn with rotting seaweed." Anglers even use them as bait for pompano and redfish (Orkin).
Who is who at the beach
None of the top search results put all four side by side, so we did. Each cell cites the source that speaks about that animal. The names overlap, and the sources disagree on which insect "sand fly" should mean, so read the headers as "what people usually mean."
| Biting midge (the US beach "sand fly") | Phlebotomine sand fly (the entomologist's "sand fly") | Beach hopper (the usual "sand flea") | Chigoe or jigger flea (the tropical "sand flea") | |
|---|---|---|---|---|
| What it is | Tiny fly, genus Culicoides; also no-see-um, sand gnat, punkie (Arizona Extension, Clemson) | Tiny, hairy, mothlike fly, family Psychodidae (Merck) | Small jumping crustacean, family Talitridae (Orkin, Terminix) | A true flea, Tunga penetrans (Orkin, Terminix) |
| Does it bite? | Yes, females only (Clemson) | Yes, females feed on blood (Merck) | No (Orkin, Terminix, KQED) | It can burrow into skin (Orkin, Terminix) |
| Size | About 1/16 inch (Clemson); 1/8 to 1/4 inch (Arizona Extension) | 1.5 to 3.5 mm (ECDC); 1.5 to 4 mm (Merck) | About 1/4 inch (Orkin); 1/4 to 1 inch (Terminix) | Not in our sources |
| Where | Near water: beaches, marshes, swamps, ponds; salt marsh and mangroves (Arizona Extension, Clemson, UF) | Mostly tropical and subtropical (Merck); stays within a few hundred meters of breeding sites (ECDC) | US beaches near the high-tide mark (Orkin) | Caribbean, Central and South America, parts of Africa and India (Orkin) |
| When | Dawn and dusk; cloudy, calm days; year-round where winters are warm (Arizona Extension, UF) | Mostly dusk and night (ECDC, Merck) | Night, sunset to sunrise (KQED, Orkin) | Not in our sources |
| What keeps it off you | Breeze or fan, light colored long sleeves and pants, a suitable repellent used per its label (UF, Clemson, Arizona Extension) | Air currents, even light wind (Merck, ECDC) | Nothing needed; shake out towels (Terminix) | Not in our sources |
Do sand fleas bite?
No. Terminix states that "Sand fleas do not bite humans," and Orkin says true sand fleas cause no harm to people or pets. Both point elsewhere: the itchy bites people blame on "sand fleas" at beaches and marshes usually come from sand flies and biting midges. Terminix also names the chigoe flea, a different flea that Orkin says is not a concern unless your travels take you to the tropical regions in the table.
What do sand fly bites look like?
For biting midges, Clemson Extension describes "an itchy, raised spot on their victim's skin very similar in appearance to a mosquito bite." They are so small that many people notice the bite before they ever see the biter, which is how the no-see-um got its name. For a closer look, see our guide to what no-see-um bites look like.
When and where sand flies bite
Timing is the most useful thing to know about biting midges:
- Time of day: usually dawn or dusk (University of Arizona Extension), plus daytime on cloudy days when winds are calm (University of Florida).
- Season: largest numbers in summer, but year-round in places with warm winters (University of Arizona Extension). Clemson Extension notes the first killing frost in fall "is always a welcome relief for those that enjoy spending time outdoors."
- Place: near water. University of Florida entomologists say "Coastal areas provide primary habitat for biting midges," with salt marsh and mangroves as major sources. They do not establish inside homes.
- Wind: they are weak fliers, so a breeze matters (University of Florida, Clemson Extension).
Phlebotomine sand flies are similar: most species feed at dusk and at night, and even light wind can reduce biting (ECDC).
Can you bring sand fleas home?
Very unlikely. Terminix explains that beach hoppers need moist sand and cannot live long away from the shore, and Orkin agrees. Still, shake out towels and blankets, rinse gear with fresh water, and use a beach mat or towel between you and the sand.
Your golden hour beach plan
Golden hour is the best part of a beach day, and it overlaps with the time biting midges like best. A few small choices keep the evening about the sunset.
- Pick a breezy spot. Midges and phlebotomine sand flies are weak fliers (University of Florida, ECDC), and the Merck Veterinary Manual notes that even slight air currents deter sand flies. An open stretch of sand with a sea breeze beats a sheltered corner by the marsh grass.
- Cover ankles and legs. The University of Arizona Extension suggests light colored long sleeved shirts, pants, shoes and socks.
- Apply repellent before golden hour. The University of Arizona Extension notes that repellents effective against mosquitoes are effective against biting midges. Choose a suitable repellent and always follow the label.
- Set up the porch for later. A ceiling fan or box fan helps, since midges are small enough to be blown off course (Clemson Extension). For screens, the University of Arizona Extension recommends 30 x 30 mesh, and Clemson Extension says 20 x 20 or smaller.
- Stay for the show. After dark, take a flashlight to the high-tide line and watch the beach hoppers come out to clean up the seaweed.
One honest note: you can't clear a beach of midges. Clemson Extension says area-wide control is nearly impossible, because new ones keep arriving from nearby breeding sites. Timing, breeze, clothing and repellent are what make the evening comfortable.
Our pick for beach evenings
We built Bloc Off Mosquito Repellent Spray for these hours outside. It uses 8% plant-based PMD (para-menthane-3,8-diol) derived from lemon eucalyptus, with 6+ hours of lab-tested protection against mosquitoes and ticks. It is DEET-free and alcohol-free, with aloe vera and chamomile, plus shiso (perilla) for a soft, fresh feel. My co-founder Cassidy Huang and I spent two years with a Taiwan-based chemist getting the formula right. The 4 oz bottle is $15.00.
To be clear, we make no sand fly or midge claim for it. It is our spray for mosquito evenings, and it pairs well with the breeze, clothing and timing steps above. For a lighter beach bag, our Bloc Off Mosquito Repellent Wipes come as 10 individually wrapped wipes for $13.00.
FAQ
Do sand flies bite?
Yes, but only the females. Clemson Extension says female biting midges need a blood meal to produce eggs and feed mainly early and late in the day. The Merck Veterinary Manual says female phlebotomine sand flies also feed on blood.
Are sand fleas real fleas?
No. Sand fleas are beach hoppers, small crustaceans in the family Talitridae. As KQED's Deep Look puts it, "they don't bite and they aren't fleas."
Are sand flies and no-see-ums the same?
In the US, usually yes. The University of Arizona Extension says no-see-ums are also known as punkies or sand flies, though University of Florida entomologists call that name technically incorrect. Our no-see-ums guide has the full story.
How do I get rid of sand flies at the beach?
You can't clear a whole beach; Clemson Extension says area-wide control of biting midges is nearly impossible. What works is a breezy spot, planning around dawn and dusk, light colored long sleeves and pants, and a suitable repellent used according to its label.
Can sand fleas get in your skin?
The beach hopper cannot. Terminix says sand fleas "do not burrow or bite into skin or feed on blood." The burrowing one is the chigoe or jigger flea, a different flea found in tropical areas such as parts of South America and Africa (Orkin, Terminix).
Written by Tanya Lee, Co-Founder of The Superbloc. Sources: University of Arizona Extension; Clemson Cooperative Extension HGIC 2489; UF/IFAS Extension EENY 349; Merck Veterinary Manual; ECDC phlebotomine sand fly factsheet; Orkin; Terminix; KQED Deep Look.