Don Hoi Lot (Thai: ดอนหอยหลอด) 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 is settled by the Razor Clam shell (Solen regularis), which also gave the site its Thai name. The site has the largest population of this shell species, which is endemic to the northern Gulf of Thailand.