Beginning the week of August 22, transit riders will be able to enjoy cell service while traveling underground.

Sound Transit has partnered with Mobilitie, a wireless infrastructure provider, to create and install a Distributed Antenna System (DAS) that benefits the rider while improving safety and security underground.

By late September, the system will provide coverage to the tunnel between University of Washington and Westlake in downtown, followed by downtown and Beacon Hill in early 2017.

Cell service providers in Seattle can access the system through license agreements with Mobilitie, which is funding and maintaining the network under an agreement with Sound Transit.

T-Mobile customers are the first to have cell access between University of Washington and Westlake. Verizon and AT&T customers are scheduled to have access next month, with Sprint coming soon.

Mobilitie may also provide cell service in the 8.2 miles of new tunnels and two underground stations as part of the Northgate light rail extension opening in 2021.