Don Hoi Lot (Thai: ดอนหอยหลอด, pronounced [dɔ̄ːn hɔ̌j lɔ̀ːt]) is a sandbar off the coast of Samut Songkhram Province at the northwestern tip of the Bay of Bangkok. The sediments of the Mae Klong River together sediments from the sea form a system of mudflats, which are populated by razor clams (Solen regularis), which also gave the site its Thai name. The site has the largest population of this species, which is endemic to the northern Gulf of Thailand. Also 18 bird and 42 invertebrate species are recorded at the mudflats and the adjoining coastal mangrove forests. The mudflat Don Nai is on the coast. At Chu Chi village several seafood restaurants offer the local clams. Nearby, the highly revered shrine of Prince Chumphon Khet-Udomsak attracts Thai visitors.
Since 5 July 2001 the site has been registered as Ramsar site number 1099. Don Hoi Lot is named after the tubular shellfish, known as razor clams or “worm shells” in English. the area covers 3 km. width and 5 km. long in Tambon Bang Chakreng.
Don Hoi Lot has become a place for people to visit on the weekend. Shell digging on the sandbank is one of the activities for visitors, people mostly come here to do shopping at seaside market and restaurants. On the weekend, the side of the coastal road is transformed to market of fresh and prepared seafood, packaged local products, fresh fruit, Thai sweets and a few Don Hoi Lot T-shirts.
The best time of the year for visiting is between March-May because the water level is lower and the sandbanks will be exposed. Tourists can rent the boat from Aphon Pavilion (near the Krommaluang Chumphonkhetudomsak Shrine) to the sandbar. The boat can take a maximum of 6 people for a rate of around 60 baht. To visit the bay mouth, the boat rental is 200 baht per boat with maximum 5 people.
Coordinates: 13°22′N 100°2′E / 13.367°N 100.033°E