The study of mesons and baryons which contain at least one charm quark is referred to as open charm physics. It offers the possibility to study up-type quark transitions. Since the q ̧uark can not be treated in any mass limit, theoretical predictions are difficult and experimental input is crucial. BESIII collected large data samples of e+e− collisions at several charm thresholds. The at-threshold decay topology offers special opportunities to study open charm decays.

We present a selection of recent BESIII results: The measurement of the branching fraction D+s → pn,  the observation of the decay D->a0(980)0 e+ nu_e, the search for the semi-leptonic decay D+->D0 e+ nu_e and the search for rare decays D → h(h′)e+e−.