Wearable antennas are designed to function to be worn. These antennas are commonly used in wearable wireless communication. The three-element flexible array antenna is designed with ECE-Shaped slots by using flexible felt material as substrate with a thickness of 3mm, and its permittivity is 1.22 to give good insulation. This array antenna is designed for a frequency of 2.4 GHz with dimensions of 173 mm by 50 mm, and the distance between patches is chosen to be 20 mm. The return loss is at S11 = -15 dB. This design can cover the ISM band and provide good performance. The parameters that are listed from the designed antenna are the reflection coefficient, VSWR, gain, directivity, and specific absorption rate (SAR), which should be less than safety levels. The designed three-element flexible array antenna is applicable for biomedical applications.