This study reports cryoEM structures of the bacterial flagellar switch in three states: the counterclockwise (CCW) pose of the MS-ring and C-ring, the clockwise (CW) pose of the C-ring alone, and the CW pose of the C-ring bound to a regulator. These structures reveal how the flagellar motor rotates and switches direction. The C-ring, which contains FliG, FliM, and FliN subunits, acts as the 'switch' that controls the direction of rotation. In the CCW pose, the FliF/FliG domains rotate 180°, moving the MotA/B binding site inward. In the CW pose, the regulator specifically binds to the C-ring, facilitating switch assembly and direction change. The structures show that the C-ring transmits torque to the flagellar rod, enabling bacterial chemotaxis. The switch also connects to the MS-ring, which transmits direction and speed to the flagellum. The study provides insights into the mechanism of bacterial chemotaxis and bidirectional motor rotation, highlighting the role of conformational changes and domain swaps in the switch. The findings advance understanding of how the flagellar motor functions and how response regulators influence rotation and torque transmission. The structures also reveal the architecture of the flagellar motor, including the roles of the L-ring, P-ring, and other components in supporting and buffering rotation. The study underscores the importance of structural dynamics in the function of the flagellar motor and the interplay between the switch and other components in controlling bacterial movement.This study reports cryoEM structures of the bacterial flagellar switch in three states: the counterclockwise (CCW) pose of the MS-ring and C-ring, the clockwise (CW) pose of the C-ring alone, and the CW pose of the C-ring bound to a regulator. These structures reveal how the flagellar motor rotates and switches direction. The C-ring, which contains FliG, FliM, and FliN subunits, acts as the 'switch' that controls the direction of rotation. In the CCW pose, the FliF/FliG domains rotate 180°, moving the MotA/B binding site inward. In the CW pose, the regulator specifically binds to the C-ring, facilitating switch assembly and direction change. The structures show that the C-ring transmits torque to the flagellar rod, enabling bacterial chemotaxis. The switch also connects to the MS-ring, which transmits direction and speed to the flagellum. The study provides insights into the mechanism of bacterial chemotaxis and bidirectional motor rotation, highlighting the role of conformational changes and domain swaps in the switch. The findings advance understanding of how the flagellar motor functions and how response regulators influence rotation and torque transmission. The structures also reveal the architecture of the flagellar motor, including the roles of the L-ring, P-ring, and other components in supporting and buffering rotation. The study underscores the importance of structural dynamics in the function of the flagellar motor and the interplay between the switch and other components in controlling bacterial movement.