If you live in the Southeast, you have probably already met one, or at least walked into one of its webs. The Joro spider is big, bright yellow, and builds across gaps people want to walk through. It is also new here: the first confirmed North American record dates to 2014.
This page covers what the animal is and how to recognize it. Three companion pages go deeper on the questions people actually search for: whether they are dangerous, what to do about the webs, and where they have reached so far.
What It Is
The Joro spider is Trichonephila clavata, described by L. Koch in 1878. It is an orb-weaver, in the family Araneidae, and it is native to East Asia. Penn State Extension gives the native range as Japan (excluding Hokkaido), North and South Korea, China, Taiwan, Vietnam, and India.
In its native range it has one generation per year, and the same pattern holds in the United States: spiderlings in spring, conspicuous adults in late summer and fall, egg sacs before winter, and then the adults die off.
Identification
Almost every Joro spider anyone photographs is an adult female. She is the large, colorful one sitting in the middle of a golden web. The male is a fraction of her size and easy to overlook.
The female
- Body length: 0.67 to 1.2 inches (17 to 30 mm), per University of Georgia Extension. Joro Watch describes adult female bodies as up to 1.25 inches long.
- Leg span: Penn State Extension gives up to 4 inches. Clemson Extension describes females as having a span of 3 or more inches with the legs outstretched. Both figures are cited here because they are separate published measurements, not one number rounded two ways.
- Top of the abdomen: bright yellow with broad bluish-green bands running across it.
- Underside of the abdomen: large red markings. This is the single most useful confirming feature, and it means looking at the spider from below, through the web.
- Legs: long and black with yellow or yellow-orange bands. Rarely, they are all black.
The male
- Body length: 0.16 to 0.31 inches (4 to 8 mm), per University of Georgia Extension. Joro Watch gives approximately 0.25 inches.
- Color: brown, not yellow. The abdomen is an elongated oval with two long yellowish stripes along the sides and a dark brown stripe down the middle.
- Males are usually found on the edge of a female’s web rather than in a web of their own.
Lookalikes
Joro Watch lists three spiders that get mistaken for Joros in the Southeast. Checking against them takes a few seconds and is worth doing before you report a sighting.
- Golden silk orb-weaver (Trichonephila clavipes) — the closest match, and a relative. It has dense black tufts of hair near the leg joints on the first, second, and fourth pairs of legs, and its abdomen is yellow-orange with silvery white spots rather than banded yellow and bluish-green.
- Yellow garden spider (Argiope aurantia) — a distinctive yellow and black abdomen, and a web that often carries a zig-zag of thick silk above and below a dense center.
- Banded garden spider (Argiope trifasciata) — many thin black, yellow, and silvery white bands across the abdomen, rather than a few broad ones.
If you are still unsure, photograph the underside. The large red markings on the belly are what separate a Joro from all three.
Where It Came From
The first confirmed record in the New World came from northeast Georgia in the fall of 2014. Specimens were collected around residential properties in Barrow, Jackson, and Madison counties, with many of the early reports clustered near Braselton and Hoschton, close to warehouse and distribution facilities along the Interstate 85 corridor. E. Richard Hoebeke and Byron J. Freeman of the University of Georgia confirmed the identification and published the record in PeerJ in 2015.
On how it got here, the University of Georgia’s own account is careful and worth quoting in substance rather than paraphrasing loosely: the spider arrived accidentally as a hitchhiker, either in shipping containers, in packing materials such as pallets and crates, or on live plant material. The proximity of the earliest records to freight infrastructure is consistent with that.
Nobody knows exactly when it arrived. Clemson Extension states that it was likely introduced several years before its discovery, without naming a year. We have seen a specific earlier arrival date circulated elsewhere; because no source in the preference order we use gives one, it is not on this page.
How It Spreads
Two mechanisms, working at very different scales.
Ballooning is the natural one. Spiderlings climb to a high point, release strands of silk, and let wind currents carry them. Penn State Extension reports that ballooning can move them tens to hundreds of miles; University of Georgia Extension notes that the silk strands catch wind currents that can carry the spiders many miles, even between islands. This is why the range expands as a spreading edge rather than as isolated dots.
Accidental human transport is the other. The species arrived on this continent in freight, and the same routes keep working. Isolated populations well outside the contiguous range are generally assumed to have arrived this way, which is why the current range map has outliers in it.
The Year in a Joro
One generation per year, and it runs roughly like this in the Southeast:
- May onward: juveniles begin showing up, small and easy to miss.
- Late July and August: more mature spiders become obvious as webs get larger.
- September and October: peak observations. This is when the big golden webs are at their most conspicuous, and when almost all the photographs get taken.
- Mid-October through November: egg sacs are laid. Joro Watch describes them as dense white silk sacs attached to leaves, tree bark, and flat structures, each containing 400 to 500 eggs.
Joro Watch gives the current southeastern peak as August through October (as of August 21, 2026), with sporadic finds in the months either side.
Questions
What is a Joro spider?
The Joro spider is a large orb-weaving spider, Trichonephila clavata, native to East Asia. It was first confirmed in North America in northeast Georgia in 2014. Adult females are the ones people notice: a bright yellow abdomen with broad bluish-green bands across the back, large red markings underneath, and long black legs banded in yellow.
How big does a Joro spider get?
University of Georgia Extension gives the adult female body length as 0.67 to 1.2 inches. Penn State Extension puts the leg span at up to 4 inches, and Clemson Extension describes females as spanning 3 or more inches with their legs outstretched. Adult males are far smaller, roughly a quarter of an inch, and brown rather than yellow.
Where did Joro spiders come from?
They are native to Asia, including Japan, North and South Korea, China, Taiwan, Vietnam, and India. University of Georgia researchers who confirmed the first North American record concluded the spider arrived accidentally as a hitchhiker, either in shipping containers, in packing materials such as pallets and crates, or on live plant material. Clemson Extension notes it was likely introduced several years before anyone noticed it in 2014.
How do Joro spiders spread so quickly?
Young spiderlings disperse by ballooning. They release strands of silk that catch wind currents and carry them away from where they hatched. Penn State Extension reports that ballooning spiders can travel tens to hundreds of miles, and University of Georgia Extension notes the technique can carry them even between islands. Adults do not balloon, but they do get moved accidentally by vehicles and freight.
When are Joro spiders most visible?
Joro Watch reports that the peak in the southeastern United States is currently August through October. University of Georgia Extension notes juveniles appear as early as May, with more mature spiders in late July and August and observation peaks in September and October. Egg sacs are laid from mid-October through November.
Sources
Every factual claim on this page traces to one of the following. Where two sources give different figures for the same measurement, both are reported above rather than averaged.
- University of Georgia Cooperative Extension. Joro Spider: Trichonephila clavata (Circular 1273). Revised June 16, 2026. https://fieldreport.caes.uga.edu/publications/C1273/
- Joro Watch, UGA Center for Invasive Species and Ecosystem Health. Species Info. Accessed August 21, 2026. https://jorowatch.org/species-info/
- Penn State Extension. JorĹŤ Spiders. September 8, 2025. https://extension.psu.edu/joro-spiders
- Clemson Cooperative Extension, Home & Garden Information Center. The JorĹŤ Spider. November 21, 2024. https://hgic.clemson.edu/factsheet/the-joro-spider/
- University of Georgia. UGA scientists confirm first North American record of East Asian Joro spider. March 17, 2015. https://news.uga.edu/first-north-american-record-east-asian-joro-spider-0315/
- Joro Watch, UGA Center for Invasive Species and Ecosystem Health. Joro Watch Season. Accessed August 21, 2026. https://jorowatch.org/season/