This letter presents a trimode multi‐functional patch antenna for GPS and wireless communication applications. The antenna consists of a folded annular slot, a section of coaxial cable, shorting copper columns and the ground plane. Tri‐band operation is realized by exciting three different working modes including microstrip antenna mode, slot antenna mode and monopole antenna mode. The proposed antenna is designed to cover the GPS L1 and L2 bands, UMTS‐band 5. At the GPS bands, the antenna is unidirectional with right‐hand circular polarization. At the telecommunication band, an omnidirectional radiation pattern is realized with linear polarization. The design is fabricated by standard PCB technologies, and its performance is validated by measurement.