Накхонситхаммарат
The route runs eastward through Surat Thani Province to the east coast, then southward to Nakhon Si Thammarat Province. It ends at Ban Tha Pae, about 10 km north of Nakhon Si Thammarat town. Highway 4012 then connects Ban Tha Pae to Nakhon Si Thammarat town.