Below is a list of Union City CA zip codes. For your research we have also included Union City Area Code, Time Zone, UTC and the local Alameda County FIPS Code. Each Union City California zip code has a center Longitude / Latitude point (the Union City center is -122.01599884033 / 37.602199554443). For your convenience we have also indicated if that zip code in Union City observes Daylight Savings time.