Embodiments of the present disclosure relate to methods and devices for transmission by selecting between uplink resources. According to a method implemented by a terminal device in a communication system, a configuration of a first resource is received from a network device, the first resource being a grant-free resource. An uplink grant is received from the network device, indicating a second resource for use in a transmission time interval. The terminal device determines, based on the configuration of the first resource, whether the first resource is available in the transmission time interval. In response to determining that the first resource is available and possibly in response to a predefined condition associated with a logical channel for the terminal device is met, the terminal device transmits uplink data to the network device using the first resource.