To increase the efficiency of transcritically operated CO2 refrigeration systems, ejectors are often used to recover a portion of expansion losses. However, current CO2 ejector systems are limited to low to medium pressure lifts, risking lower efficiency, flow separation, and backflow during ejector operation outside the design condition. In response to these challenges, a novel ejector cycle with an additional subcooling heat exchanger has been developed. In this work, an ejector was prototyped using an existing numerical design tool and integrated into a CO2 test stand with a subcooling heat exchanger for experimental testing. The optimized ejector subcooling cycle was compared with two different reference systems: one with flash gas bypass (FGB), and the other one with flash gas compressor (FGC), neither of which employed an ejector. The results showed that the optimized ejector subcooling cycle achieved efficiency increases of up to 40% compared to the FGB system and up to 17% with the FGC.