A method comprising: receiving, by a mobile device, a first location request requesting a location of the mobile device, the first location request specifying a requested accuracy threshold, wherein the mobile device is a wearable computing device; determining, by a location determination subsystem of the mobile device, a first location estimate of the mobile device, the first location estimate being associated with an uncertainty value that is determined by the location determination subsystem; determining whether the uncertainty value satisfies the requested accuracy threshold; in response to determining that the uncertainty value does not satisfy the requested accuracy threshold, determining, by the mobile device, that the location determination subsystem of the mobile device is incapable of determining the location of the mobile device at the requested accuracy threshold under current conditions; in response to determining that the location determination subsystem of the mobile device is incapable of determining the location of the mobile device at the requested accuracy threshold, establishing a wireless communication channel between the mobile device and a companion device using a protocol in which a communication range between the devices is less than the requested accuracy threshold and submitting, over the wireless communication channel, a second location request by the mobile device to the companion device that has paired with the mobile device; and in response to receiving a response to the second location request from the companion device, the response including the location assistance information, determining a second location estimate of the mobile device based on the location assistance information, and submitting the second location estimate corresponding to the location assistance information as a response to the first location request. receiving, by a mobile device, a first location request requesting a location of the mobile device, the first location request specifying a requested accuracy threshold, wherein the mobile device is a wearable computing device; determining, by a location determination subsystem of the mobile device, a first location estimate of the mobile device, the first location estimate being associated with an uncertainty value that is determined by the location determination subsystem; determining whether the uncertainty value satisfies the requested accuracy threshold; in response to determining that the uncertainty value does not satisfy the requested accuracy threshold, determining, by the mobile device, that the location determination subsystem of the mobile device is incapable of determining the location of the mobile device at the requested accuracy threshold under current conditions; in response to determining that the location determination subsystem of the mobile device is incapable of determining the location of the mobile device at the requested accuracy threshold, establishing a wireless communication channel between the mobile device and a companion device using a protocol in which a communication range between the devices is less than the requested accuracy threshold and submitting, over the wireless communication channel, a second location request by the mobile device to the companion device that has paired with the mobile device; and in response to receiving a response to the second location request from the companion device, the response including the location assistance information, determining a second location estimate of the mobile device based on the location assistance information, and submitting the second location estimate corresponding to the location assistance information as a response to the first location request.