From the Chao Phraya River to Khlong Bangkok Noi

he Chao Phraya River has long served as the lifeblood of the Thai people. Yet few realize that Khlong Bangkok Noi, which flows through the Thonburi side of modern-day Bangkok, was once part of the river’s original course—before natural forces and human intervention redirected the flow of this major waterway.

Before the 16th century, the Chao Phraya River followed a winding path to the sea, using what is now known as Khlong Bangkok Noi and Khlong Bangkok Yai. Khlong Bangkok Noi was excavated during the reign of King Chairachathirat of the Ayutthaya Kingdom (1534–1546 CE) as a shortcut connecting the Chao Phraya River between the mouths of Khlong Bangkok Noi and Khlong Bangkok Yai. The purpose of digging this canal was to shorten travel distances. Later, the Chao Phraya River changed its course to flow through this shortcut, causing the original river to narrow and become what is now known as Khlong Bangkok Noi., a manmade canal called Khlong Lat Bangkok was excavated to shorten the navigation route and promote trade.

The new canal gradually diverted the river’s main current, which eventually settled into the straighter path. The original, winding watercourse became a quiet backwater, later reclassified as a canal. Different sections were renamed Khlong Bangkok Noi and Khlong Bangkok Yai, depending on the area.