A swirler for mixing fuel and air is provided. The swirler includes a plurality of vanes positioned radially around a central axis of the swirler and a plurality of mixing channels for mixing the fuel and the air. At least one mixing channel of the plurality of mixing channels is defined by opposite walls of two adjacent vanes of the plurality of vanes and is comprising at least one fuel injection opening and is further comprising at least one dimple for generating a vortex of the air. Further, a combustion chamber incorporating such a swirler and a gas turbine incorporating such a combustion chamber are provided.