Modelling of diffusion anomalies in Si requires reliable data on {1 1 3} defects evolution during annealing under well defined conditions. This paper reports on the conditions under which {1 1 3} defects can alternatively dissolve or transform into dislocation loops (DLs). Our results definitely prove that the dissolution of {1 1 3} defects is not an intrinsic characteristic of these defects but reflects the competition between atomic interchange between defects and diffusion to the surface. At low temperature (up to 800 °C), these defects can reach large sizes before dissolving. If the annealing temperature is high enough (above 850 °C), these defects can transform into DLs probably through a reaction barrier. Once formed, these DLs provide internal sinks within the population and transform the non-conservative Ostwald ripening into a quasi-conservative Ostwald ripening. In the mean time, the flux of Si atoms towards the surface that drives the defect dissolution is suppressed and replaced by internal fluxes between defects of different types.