Pattaya Mayor Poramet Ngampichet has ordered an urgent inspection after what local officials described as an oil-like substance, washed ashore along more than one kilometre of beaches on Koh Larn, Chonburi.

The residue was reported on the afternoon of 9 August 2569 at Hat Tien and Hat Samae San, on the western side of the island in Moo 7, Na Kluea, Bang Lamung district. Local umbrella-and-sunbed operators and passenger boat businesses photographed the material floating offshore before waves carried it on to the beaches.

Visitors found residue on their skin

Photographs show what appeared to be large sheets of engine-oil residue breaking up into smaller clumps along the shoreline. The material was spread across the sand for a combined distance of more than one kilometre.

Thai and foreign tourists who had gone swimming reportedly found their bodies covered in the oily substance after coming out of the water. They rushed to wash themselves, according to reports.

City officials sent to identify source

Mayor Poramet said Pattaya City's administrative officials were being sent to inspect the affected areas and establish the facts.

The investigation is expected to determine both the nature of the substance and its possible source. No cause has yet been confirmed, and it remains unclear whether the material is oil or another pollutant.

Koh Larn is a popular day-trip destination from Pattaya, with visitors commonly travelling there by passenger boat from Bali Hai Pier. Authorities had not announced beach closures or restrictions at this time.

Pictures courtesy of Daily News

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10 August 2026

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Ewwww they all stepped in turds.

There's a lot of large ship traffic west (upwind and up current) of Koh Larn. It's not unknown for these guys to just dump oil overboard after an oil change, etc. It will take some key sleuthing to find the offending ship, if that's the cause. I hope the officials pursue this vigorously.

Another boost for TAT's latest campaign.

Satellite photos should reveal the source

That oil like substance looks a lot like oil.

I think an oil carrying vessel washed out the storage tanks - that's not engine oil from a small boat

Pattaya has it all. 🫪

Had the same thing at Khanom beach early last year, we go there to walk the beach but while we didnt see anything on the sand when we walked along the beach we got black crap all over our feet, looked excatly the same, oil. While we are used to finding junk all over the beach after being dumped/washed up from boats the oil was something we had never had before, unfortunately there are those that dont care what they throw/dump in the water and authorities seem to care even less.