A user terminal according to a first aspect is used in a mobile communication system. The user terminal includes: a receiver configured to receive, from a base station, candidate timing information indicating candidate timings of uplink transmission in an unlicensed band channel, which is an unlicensed band frequency channel; a controller configured to determine a transmission timing to perform the uplink transmission to the base station from among the candidate timings indicated by the candidate timing information, by monitoring the unlicensed band channel; and a transmitter configured to transmit uplink data to the base station via the unlicensed band channel at the transmission timing.