RAYONG — 6 June 2026, Millions of pink sea cucumbers have washed up along a beach in Thailand’s eastern province of Rayong in a rare natural phenomenon that has attracted widespread attention from tourists and marine experts.
Large numbers of the marine animals were found stranded along Suan Son Beach in Phe subdistrict, Mueang district, turning hundreds of metres of shoreline a reddish-pink colour and drawing crowds of visitors.
Following reports of the unusual event, the Department of Marine and Coastal Resources ordered an urgent investigation.
Officials from the department’s Regional Marine and Coastal Resources Office 1 surveyed the area and identified the animals as pink sea cucumbers, also known as pink thorny sea cucumbers, scientifically classified as Cercodemas anceps.
Sea cucumbers are soft-bodied marine invertebrates that live on the seabed. They have elongated, cylindrical bodies resembling cucumbers or sausages and can range in colour from bright pink to orange-red.
According to the department, sea cucumbers play an important ecological role by breaking down decaying organic matter and other debris on the ocean floor. Because of this function, they are often referred to as the “housekeepers of the sea” for helping maintain the health and balance of marine ecosystems.
Authorities believe the mass stranding was caused by rough seas, strong waves and storm-related conditions that swept the animals from the seabed onto the shoreline.
Officials described the event as a rare natural occurrence.
The department advised tourists to avoid direct contact with the sea cucumbers, warning that some species can release defensive substances that may cause skin irritation, particularly in people with sensitive skin.
