Moon jellyfish
Aurelia aurita
Translucent saucer with four pale-pink horseshoe markings. A mild sting that's often barely noticeable. Present year-round but most visible in summer.
Wildlife guide · Texas Coastal Bend
When is jellyfish season in Port Aransas & Corpus Christi.
Short answer: stings are most likely from late spring through early fall, with two clear Portuguese man o' war peaks — spring (April–May) and fall (September–October) — when southeast winds push them toward shore. Winter and early spring are essentially jellyfish-free. Port Aransas and Corpus Christi share the same Gulf waters, so the timing is the same across the region.
Port Aransas and Corpus Christi sit about thirty minutes apart on the same stretch of Texas coast, so they share the same jellyfish calendar. The species you'll see — and the months they show up — are driven by Gulf water temperature and the prevailing southeast wind, not by which town you're standing in. The one meaningful difference is exposure: the open-Gulf beaches (Mustang Island in Port Aransas, plus North Padre Island and Whitecap Beach near Corpus Christi) catch the wind-blown Portuguese man o' war, while the calmer, more protected bayfront water along Corpus Christi Bay sees far fewer of them. Whichever beach you choose, the purple flag is your daily signal that dangerous marine life has been reported.
What you'll see, and when
Cabbage-head (cannonball) jellyfish
Stomolophus meleagris
Round, opaque, brown-rimmed dome. Most numerous in late summer and early fall, often washed up in numbers after onshore winds. Considered harmless to humans — the sting is very mild.
Portuguese man o' war
Physalia physalis
Not a true jellyfish but a colonial siphonophore with a blue-purple gas-filled sail and long trailing tentacles. The one to plan around: the sting is painful and it arrives in distinct spring and fall pulses on southeast winds. Even a washed-up specimen can sting for hours.
Jellyfish season month by month
The two windows to watch are spring (April–May) and fall (September–October), when Portuguese man o' war are blown ashore on southeast winds. Moon jellies drift through all summer, and cabbage-heads pile up in late summer and early fall but rarely sting. From late November through February the water is essentially jellyfish-free.
Jan
Absent
Feb
Absent
Mar
Rare
Apr
Peak
May
Peak
Jun
Possible
Jul
Possible
Aug
Possible
Sep
Peak
Oct
Peak
Nov
Rare
Dec
Absent
Absent
Rare
Possible
Peak
- Jan
- Essentially none
- Feb
- Essentially none
- Mar
- Early man o' war on south winds
- Apr
- Peak man o' war risk
- May
- Peak man o' war risk
- Jun
- Moon jellies common; man o' war drops
- Jul
- Scattered jellies
- Aug
- Cabbage-heads start arriving
- Sep
- Peak — cabbage-heads + return of man o' war
- Oct
- Peak man o' war risk on south winds
- Nov
- Tapering off
- Dec
- Essentially none
If you're stung — the short version
Most stings here are mild and ease within a few hours; Portuguese man o' war stings are more painful. The key is to avoid the moves that make it worse — freshwater, ice, and urine all backfire. This is the quick version; the full step-by-step, species ID, and when to head to the ER are in the complete jellyfish guide linked below.
Get out calmly and rinse with seawater
Walk out of the surf, move to dry sand, and rinse with seawater or 5% household vinegar — never freshwater, which can trigger more stinging cells to fire.
Scrape off tentacles, then apply heat
Lift any tentacles away with a credit card or shell (not bare fingers), then soak the area in hot water as hot as is comfortable for 20–45 minutes — the most effective pain reliever for man o' war stings.
Watch for severe reactions
Seek immediate care for breathing trouble, chest tightness, dizziness, vomiting, large or central-body stings, or pain that won't ease. Call 911 for anything severe.
Jellyfish Season — FAQ
When is jellyfish season in Port Aransas and Corpus Christi?
Sting risk is highest from late spring through early fall. Portuguese man o' war arrive in two pulses — spring (April–May) and fall (September–October) — on southeast winds. Moon jellies are around all summer, and cabbage-head jellies peak in late summer and early fall but rarely sting. Late November through February is essentially jellyfish-free.
Is jellyfish season different in Corpus Christi than in Port Aransas?
No — they share the same Gulf waters and the same southeast winds, so the timing is the same. The difference is the beach you pick: the open-Gulf beaches (Mustang Island, and North Padre Island near Corpus Christi) catch the wind-blown Portuguese man o' war, while the protected bayfront water on Corpus Christi Bay sees far fewer of them.
What months have the fewest jellyfish?
From late November through February the water is essentially jellyfish-free along the whole Coastal Bend. March is usually quiet too, apart from the occasional early man o' war on a strong south wind.
Can I still swim during jellyfish season?
Usually, yes. Most summer days are fine, especially when winds are light or blowing offshore. Check the beach flags before you get in — purple means dangerous marine life has been reported — and scan the wet sand for blue man o' war sails or strings, which can still sting after they wash up.
What does the purple beach flag mean?
Purple means dangerous marine life — typically jellyfish or Portuguese man o' war — has been reported on the beach. It's posted next to the daily green/yellow/red surf-condition flag at public beach access points. Read it before you swim.
Are the jellyfish here dangerous?
Most aren't. Moon jellies and cabbage-head jellies have mild-to-negligible stings. The Portuguese man o' war is the exception — its sting is painful and occasionally serious, so it's the one worth recognizing and giving room, alive in the water or stranded on the sand. Full species ID and step-by-step first aid are in our complete Port Aransas jellyfish guide.
Plan your stay at Beached Inn
Luxury 3-bedroom beach house at Cinnamon Shore, sleeps 10. Private elevator and infinity-pool view, ~500 ft from the Gulf.
Book Beached Inn →