An electronic device and method for providing a communication service are provided. The method of operating an electronic device includes: receiving a first signal transmitted through a first band and a second signal transmitted through a second band; determining a communication mode of the electronic device for processing the first signal and the second signal based on device information or environment information of the electronic device; and processing the first signal and the second signal using at least one of a first modem or a second modem functionally connected to the electronic device based on the communication mode, wherein the processing of the first signal and the second signal includes: processing, when the communication mode is a first mode, the first signal in the first modem and the second signal in the second modem; and processing, when the communication mode is a second mode, the first signal and the second signal in the first modem.