A special Fe-boosting strategy based on the thermal conversion of new covalent porphyrin frameworks (CPFs) was developed to construct Sn-based core-dual shell nanostructures for efficiently catalyzing oxygen electroreduction (ORR). Fe-boosting carbonization of CPFs with abundant Sn species (Sn-CPFs) resulted into the formation of FeSn2@FeSnOx nanoparticles encapsulated in thin sulphur and nitrogen doped carbon shells (FeSn2@FeSnOx@S–N–C). These unique dual-shell nanostructures embedding in S–N-doped porous carbons were among the best Sn-based ORR electro catalysts in both alkaline and acidic media. Its ORR half-wave potentials reached 0.88 V in 0.1 M KOH and 0.79 V in HClO4 electrolytes, together with long-time ORR durability. Moreover, FeSn2@FeSnOx@S–N–C-900 catalyst demonstrated a peak power density of 64.5 mW cm−2 in the Zn-air batteries, comparable to the Pt/C-based counterpart (about 61.0 mW cm−2). The special Fe-boosting Sn-based dual-shell nanostructures greatly contributed to high ORR performance of this catalyst. The reported synthesis opens up a feasible route to obtain high-efficiency ORR cathode materials from p-block metals.