A drilling system for use in rotary coiled tubing drilling of deviated wellbores is provided. The drilling system includes a base, a derrick mounted on the base, a top drive system mounted on the derrick; and a coiled tubing module. The coiled tubing module is adapted to move a coiled tubing in and out of the deviated wellbore and coupled to the top drive system on the derrick. A capsule of the coiled tubing module, which holds a coil of coiled tubing, is carried and rotated by the top drive system to transfer torque to the coiled tubing moving in and out of the deviated wellbore to perform rotary coiled tubing drilling.