A computer implemented method for determining an activity of an occupant of a vehicle comprises the following steps carried out by computer hardware components: capturing sensor data of the occupant using at least one sensor; determining respective two-dimensional or three-dimensional coordinates for a plurality of pre-determined portions of the body of the occupant based on the sensor data; determining at least one portion of the sensor data showing a pre-determined body part of the occupant based on the sensor data and the two-dimensional or three-dimensional coordinates; and determining the activity of the occupant based on the two-dimensional or three-dimensional coordinates and the at least one portion of the sensor data.