This paper presents the first measured results of sub-THz photoconductive evanescent-mode waveguide single-pole single-throw switches operating in G-band. Both two-pole and three-pole devices are designed, fabricated, and measured, resulting in low insertion losses <0.4 dB and with electronically tunable isolation reaching >50 dB while requiring low optical powers. Analysis of the solid-state plasma physics reveals the viable potential to operate the switch at frequencies above 800 GHz, emphasizing the promising capabilities of this enabling platform technology for future 5G and 6G communication and radar applications at sub-THz frequencies.