Police identified the deceased as Frida Madeleine Falk, 22, Anders Tobias Larsson, 22, Elin Marita Hedbris, 21, Johan Olof Nikolas Svensson, 22, and their taxi driver, Wichit Phromluang, 26, from Udon Thani Province.
The crash happened on the Kok Kloy-Phang Nga bypass road, just north of Phuket, while the group were travelling from Patong to Chumphon Province for a diving trip.
Police said the truck crossed through the median strip and then hit the taxi.
The driver of the truck fled from the scene.
The truck belongs to a Narathiwat-based Chokepattama Company. Police will contact the owner of the truck for details of the driver.