Yes, cell phones generally work on BART (Bay Area Rapid Transit) in 2026, though the experience differs between the underground tunnels and the above-ground tracks. BART has worked extensively with major carriers like Verizon, AT&T, and T-Mobile to install "leaky feeder" cables and small cell nodes throughout the underground sections in San Francisco and Oakland, including the Transbay Tube. While you may experience brief "dead zones" or hand-off lag when entering or exiting tunnels, 5G connectivity is now standard across most of the subterranean network. Furthermore, in early 2026, BART launched free high-speed Wi-Fi 6E at major stations like SFO, Powell Street, and Embarcadero to ease the strain on cellular networks during high-traffic events. While "on-train" Wi-Fi is still being rolled out across the entire fleet, your mobile data plan should remain functional for most of your journey. To ensure the best connection, passengers often use the station Wi-Fi for heavy downloads and rely on the cellular "tunnel" coverage for messaging and light browsing during the transit between stations.