Beachgoers are being urged to stay alert after bluebottles were sighted across the foreshore, with reports spanning Seaford, Frankston, Mornington and Safety Beach, and further along the Peninsula to Portsea, where a swarm forced Portsea back beach to close for periods this week.
Frankston City Council also issued a warning, advising swimmers and walkers to stay aware because bluebottles have long venomous tentacles and can sting in the water or when washed up on sand. The council urged people to follow surf lifesaver advice when visiting local beaches.
Portsea back beach closed amid bluebottle swarm
Portsea back beach was closed on Tuesday 16 December 2025 and for part of Wednesday 17 December 2025 after being inundated with bluebottles, according to a report citing Portsea Surf Life Saving Club.
The same report attributed the influx to strong easterly winds pushing bluebottles towards shore and said sightings were also reported at other beaches including Gunnamatta and Mount Martha South Beach.
Natural beach wash-ups can occur
Authorities note that Port Phillip Bay is home to a range of marine species and that warmer weather and changing conditions can bring marine life closer to shore.
This can include large numbers of jellyfish, sea stars, seaweed, or other marine life washing ashore, with experts describing these events as natural and unpredictable and often resolving between tides.
With warmer weather drawing more families to the coast, first aid authorities say knowing what to do after a sting can help reduce pain and prevent further injury.
Bluebottle stings: Do’s and Don’ts
Do
- Get out of the water to avoid further stings.
- Rinse the sting with seawater, not fresh water.
- Remove any remaining tentacles carefully. Take care not to sting yourself.
- Place the affected area in hot water (hot but not scalding) and keep it there for around 20 minutes to help manage pain.
- Seek help from a surf lifesaver if one is on duty.
- Call 000 if there are severe symptoms, including breathing difficulty, chest pain, collapse, or if you are seriously concerned.
Don’t
- Do not pee on a sting. It is a myth and is not recommended.
- Do not rub the area with sand, towels or hands.
- Do not apply vinegar for bluebottle stings. Health authorities warn it may increase pain.
- Do not rinse with fresh water.
St John Victoria has published first aid guidance on managing jellyfish stings and injuries caused by Australian venomous marine creatures.
