The Link kiosks will provide Wi-Fi with speeds of up to 1Gbps to nearby users, free UK landline and mobile calls and phone charging points.
BT said "at least 750" will appear across the capital over the next year, as well as being introduced in other cities.
The service will be funded through advertising on the devices.
A touch-screen tablet on the kiosks will give access to maps, directions and local services while sensors will capture real-time data of the local environment such as pollution levels and air temperature.
