This paper presents a low-profile, lightweight, and flexible antenna to work over three bands used by wearable electronic devices. Wearable applications demand the flexibility of the antenna, and this is achieved by employing a nickel-copper-coated ripstop conductive fabric of the radiative part (patch and ground) and a silicon-based polymer, polydimethylsiloxane (PDMS), for the substrate material. The geometry of the antenna is a triangular patch with two stubs and two slots added to the antenna to enhance the impedance and matching bandwidth. The suggested antenna offers three frequency bands at 3.5, 5.15, and 6.6 GHz, which enable 5G-enabled wearables, Wi-Fi devices, and short-range sensing applications, respectively. The proposed work is validated by studying performance parameters such as S-parameter, gain, and radiation pattern. To make the proposed antenna suitable for wearable devices, conformal analysis, SAR analysis, and gain on the body are studied. The conformal analysis shows a good agreement with the flat antenna analyzed in terms of S11, gain, efficiency, and radiation pattern. The design is also retrieved on a human body phantom to investigate both SAR and gain using the Sim4Life EM simulation tool. Moreover, the antenna’s performance is compared with recently published articles. The findings provided by the suggested antenna, together with comprehensive comparisons to existing literature, demonstrate that the antenna exhibits robust performance and is well-suited for incorporation into wearable electronic devices.