This paper outlines the design of a six-element multiple-input–multiple-output (MIMO) antenna with pattern diversity for industrial scientific medical (ISM)/5G-enabled wireless body area networks (WBANs). Within the MIMO configuration, each element has a quasi-yagi antenna configuration implemented on an ultrathin microwave laminate. The proposed quasi-yagi antenna has a small form factor of 25 × 25 mm, featuring a dipole-like radiator excited through a microstrip-line to tapered slot-line transition. The antenna’s radiators are patterned to ensure a dual-narrow impedance bandwidth. The conventional strip-line director in the planar yagi is replaced with a semicircular loop-like director, enhancing directional radiation patterns. This proposed flexible antenna offers versatile functionality by operating at both ISM standards of 2.45 GHz and the 5G wireless local area network standard at 3.5 GHz. The quasi-yagi elements are strategically distributed in a hexagonal formation to construct the six-element MIMO scheme with pattern diversity, resulting in a tangential radiation pattern suitable for on-body communication. Following fabrication, the prototype MIMO antenna’s simulation results are validated through real-time measurements. The proposed antenna exhibits an average gain exceeding 3.5 dBi across both operating bands. Furthermore, the proposed MIMO antenna exhibits promising performance metrics suitable for densely cluttered WBAN environments.