We built a phased array system for high-power simultaneous wireless information and power transfer (SWIPT) using four 5.8-GHz injection-locked magnetrons. In the magnetron injection-locked state, the transmission efficiency was measured at different modulation rates. The fluctuation in the transmission efficiency was not more than 0.5%. We observed that dynamic beamforming does not affect communication quality. Using the magnetron phased array system, SWIPT experiments revealed that a frequency modulated (FM) signal that carries a video camera signal is transmitted and decoded during dynamic beamforming. In this SWIPT system, the main lobe transfers power, and information can be demodulated in front of the magnetron phased array from −90° to 90°. The maximum transmitted microwave power of the proposed system is 1637 W.