Belle II is a major upgrade of the Belle experiment and will operate at the $B$-factory SuperKEKB in Japan. Here we discuss the expected sensitivity of Belle II for $D^0 - \bar{D}^0$ mixing and $CP$ violation measurements in the charm sector, which will benefit from a factor 50 increase in statistics and an improved vertex detection and particle identification. The impact on the determination of CKM parameters from the measurements of purely leptonic $D$ mesons decays is discussed. Finally a novel method of flavour tagging to substantially increase the sample of $D^0$ and $\bar{D}^0$ is presented.