The stability and the possible application of our recently reported SiC heterofullerenes inspire the investigation of their further stabilization through ion encapsulation. The endohedral complexes X@C 12Si 8, where X=Li +, Na +, K +, Be 2+, Mg 2+, Ca 2+, Al 3+, and Ga 3+, are probed at the MPWB1K/6-311G⁎ and B3LYP/6-311G* levels of theory. The optimized geometries show the expanding or contracting capability of C 12Si 8 in order to accommodate metal ion guests. The inclusion energies indicate the stability of the complexes compared to the components. Meanwhile, the calculated binding energies show the stabilization of C 12Si 8 through the inclusion of Be 2+, Mg 2+, Al 3+, and Ga 3+. The host–guest interaction that is probed through NBO atomic charges supports the obtained results. This study refers to “metal ion encapsulation” as a strategy for stabilization of SiC heterofullerenes.