5 16 127。 According to the inquiry, the postcode of Shiwan Town, Huizhou City, Guangdong Province is 5 16 127. Huizhou is a prefecture-level city in Guangdong Province, located on the east bank of Guangdong-Hong Kong-Macao Greater Bay Area, with Luofu Mountain as its back and Daya Bay as its south. Dongjiang River winds more than 65,438+000 kilometers and is one of the central cities in the Pearl River Delta.