Answer: T-Mobile . T-Mobile’s median 5G download speeds clocked in at 135.17 Mbps on Speedtest, compared to second-place Verizon at 78.94 Mbps. AT&T came in just behind Verizon at 72.46 Mbps. T-Mobile also dominated in 5G availability at 64.4 percent compared to less than 50 percent for both AT&T and Verizon.