This letter proposes an approach for the realization of three-dimensional flexible antennas based on the use of liquid metal and additive printing technologies. As a representative example, a miniaturized inverted-F antenna (IFA) operating at 885 MHz and suitable for wearable applications is designed, realized, and measured. The antenna sensitivity to the bending is strongly reduced, thanks to the proposed structure. The performance of the antenna in several bent configurations and in presence of the human body has been evaluated.