The old Customs House (Thai: ศุลกสถาน, RTGS: Sunlakasathan) is a historic building in Bangkok, located on the eastern bank of the Chao Phraya River in Bang Rak District. It was built in 1888 as one of the many Western-style buildings commissioned by King Chulalongkorn, and was designed by Joachim Grassi in the neo-Palladian style. The building fell into disrepair during the mid-20th century. Beginning in 2019, it is undergoing restoration and re-development as a luxury hotel.