Shrimp migration in Thailand. Photo: Shutterstock Millions of freshwater shrimp are once again making an unusual nighttime journey across the rocks of Kaeng Lamduan in Thailand’s Ubon Ratchathani province, creating one of the country’s most unusual seasonal wildlife spectacles.
Known as the “Marching Shrimp,” the annual phenomenon takes place in Nam Yuen District, where large numbers of shrimp move upstream through the rocky rapids during the rainy season. The spectacle is on display throughout September, with viewing available until September 30, 2026, from 6 p.m. to 10 p.m.
The Ubon Ratchathani Wildlife and Nature Education Center is hosting the event, opening the area to visitors hoping to see the shrimp emerge from the water and move across wet rocks.
If you plan on visiting the country to watch the unusual phenomenon, don't forget about the latest entry rule changes that will go into effect starting September 15.
Ubon Ratchathani. Photo: Christopher PB / Shutterstock.comDefinitely not. The shrimp's unusual behavior is linked to the strong currents in the river. By leaving the water and moving over the rocks, they can make their way upstream without being swept away. Researchers have found that the shrimp are particularly likely to come out of the water when currents are strong, eventually returning to calmer sections of the river.
Shrimp march. Photo: ShutterstockThe migration is connected to breeding, with the shrimp moving upstream toward areas where they can mate and lay eggs. The number visible on any given night can vary depending on conditions including rainfall, water levels and the strength of the current.
That unpredictability is part of the experience. Visitors may see large numbers moving together across the rocks, but the scale of the spectacle depends on the natural conditions on the night of their visit.
The 2026 viewing season began on September 1 and continues through the end of the month. The annual event returned this year after it was closed last year because of border unrest, according to local reports.
The phenomenon has become an important attraction for Ubon Ratchathani, drawing visitors to an area better known for its natural landscapes and waterways. Local authorities have also highlighted the event as an opportunity to promote ecotourism and raise awareness of the area's freshwater ecosystems.
For anyone planning to visit, the shrimp are best viewed after dark during the designated evening hours. Conditions can change quickly during the rainy season, however, and visitors are advised to follow instructions from staff at the site. Recent heavy rainfall has also produced faster-moving water in the area, with officials warning visitors not to swim.