TikTok user @RoritarChipmunk captured the scene in a video clip showing hundreds of tourists happily logjammed at the popular Pai attraction.
The traffic of bare limbs got so congested that the river beneath disappeared from view. But the crowded conditions only boosted the festival mood, with tourists joking and laughing as they admired the views of nature.
The video rapidly went viral, with over 600,000 views as of Friday.
A staffer at the riverside Rim Pai Cottage Hotel said foreign tourists usually show up in late January and February to float down this 2km section of the river.
He said staff from nearby hotels and resorts are deployed to monitor the innertube trips for safety.
The new attraction has brought in foreign tourists, who account for over 90% of the hotel’s guests this month, he added.