On the highway going west from Bangkok toward popular beachside destinations Cha-Am and Hua Hin are the salt farms of Samut Songkhram.
The farms are blocks of ponds that stretch along the highway, and they usually dry up around January to April, the Thai dry season.
By March or April, which is the summer month in Thailand, the salt water that has been pumped into the ponds have dried up, leaving the salt.
Farmers scoop the salt into baskets and carry them into storage warehouses along the highway.
The salt farms of Samut Songkram and adjacent Samut Sakhon produce the most sea salt in the entire country.
How to get there
From Bangkok, it’s possible to hire a taxi specifically to go to the town of Samut Songkhram. It is also possible to hire the taxi for a whole day or a half day to visit the salt farms, perhaps on the way to Cha-Am and Hua Hin. The price is based on the per-kilometer rate or negotiated, depending on the number of hours the taxi is being hired.
Buses are available to the town of Samut Songkhram. This town is close to the Damnoen Saduak Floating Market, which is open early in the morning and would be a wonderful combination along with the salt farms in the afternoon, for a day trip out of Bangkok.
I would recommend renting a car from Suvarnabhumi airport. The drive toward the west coast is easy from the airport area, toward the elevated toll highway that has an exit at Samut Sakhon, the town before Samut Songkhram.
Signs for Route 4 take you all the way to Cha-Am, a favorite beachside town in the west coast of Thailand. Cha-Am is only 25 kilometers from Hua Hin, farther up the coast.