The survey named “Collaborative survey on marine debris in the Gulf of Thailand” was conducted in the upper Gulf of Thailand by the Southeast Asian Fisheries Development Center, Training Department (SEAFDEC/TD) and the National Science Museum (NSM) during 14–20 December 2019. The operation of bottom otter-trawling conducted by using the research vessel MV-SEAFDEC 2 in daytime with depth ranging 30.0–57.8 m in almost muddy substrates. Subsequently, the 936 fish specimens were collected and taxonomically identified to 131 species in 50 families. The species list is reported with sampling stations, registration numbers, sizes and identification reference. Photographs of fresh or preserved specimens for species were also provided. In addition, two species of lizardfish, Saurida fortis, and lefteye flounder, Engyprosopon keliaoense, are first recorded from the Gulf of Thailand.