Batch-fabricated SiC nanowires (NWs) and SiC@C nanocables (NCs) were heated under an argon flow at high temperature (1600−1800 °C). The ensuing product was characterized by SEM, HRTEM, EDX and XRD. As we found, the heat treatment led to the structuring of SiC NWs, whereas SiC@C NCs were completely converted into carbon nanotubes (CNTs) encapsulating faceted β-SiC nanocrystals. The growth mechanism of these nanostructures (NSs) was studied. The results collected in this study will enable us to better define use conditions of SiC-based 1D NSs at high temperatures and to understand the effect of confinement on the migration of element during annealing. These NSs could have applications in different fields such electronic and light-emitting diode.