The Bang Pakong River reaches the Gulf of Thailand here in a wide, muddy estuary, fringed with mangroves, shrimp ponds and fishing villages, about an hour east of Bangkok. It is not a classic swimming spot, and it is honest to say so: the river water is brown with silt and the shore is mostly mud. The reason to stop is the estuary itself, and if you want a proper swim, the beach at Bang Saen, about twenty kilometres south in Chonburi, is the place most people from Bangkok head for, with a long sandy shore, shady trees and stalls selling seafood.
The estuary has a surprising resident. Irrawaddy dolphins, a small, round-headed species found in coastal waters and rivers of South-East Asia, live around the river mouth, and local boat operators offer trips to see them, especially in the cooler months. Spotting their grey backs rolling in the brown water is a quiet thrill. The mangroves are also full of birds, from egrets and herons to kingfishers.
Upstream, the river flows past Chachoengsao, a provincial capital known for Wat Sothon Wararam, a huge white temple housing a revered Buddha image that draws pilgrims from all over Thailand. The countryside around is flat and green, with rice paddies, fish ponds and orchards.
On the way back to Bangkok, the main road is Highway 34, the Bang Na–Trat road, a wide, busy route lined with factories and warehouses, with heavy truck traffic. It is not a pleasant ride, but it is direct. The smaller roads along the coast and through the villages are slower but more interesting. Fuel, convenience stores and seafood restaurants are easy to find along the way. Riverside restaurants serve grilled prawns, crab and fish, and eating them by the water as the sun goes down, before the final push back into the city, is a good reward.