This study presents a novel boron–silica–tantalum (BSiTa) ternary hybrid phenolic aerogel (BSiTa-PA) that exhibits exceptional thermal insulation, mechanical strength, and electromagnetic interference (EMI) shielding properties. The aerogel is prepared through a rapid method involving sol-gel and ambient pressure drying processes, integrating organic, inorganic, and metal elements. Key findings include: 1. **Thermal Insulation and Mechanical Strength**: BSiTa-PA demonstrates low thermal conductivity (49.6 mW m⁻¹ K⁻¹) and high mechanical strength (39.4 kN·m kg⁻¹), making it suitable for extreme thermal environments. 2. **EMI Shielding**: After thermal ablation, the aerogel transforms into a carbon aerogel with high EMI shielding efficiency (31.6 dB) and load-carrying capacity (272.8 kN·m kg⁻¹). 3. **Microstructural Evolution**: The aerogel's microstructure evolves during ablation, forming small graphite domains, good ceramic structures, and abundant nanopores, which contribute to its excellent ablative resistance and EMI shielding. 4. **Structural Analysis**: XRD, SAXS, XPS, Raman spectroscopy, and MIP analyses reveal the transformation of the aerogel into a hard carbon structure with turbostratic properties, enhancing its mechanical robustness and EMI shielding performance. 5. **Conclusion**: The developed BSiTa-PA aerogel offers a promising solution for advanced thermal protection and EMI shielding in aerospace applications, laying the foundation for the advancement of multifunctional materials in extreme environments.This study presents a novel boron–silica–tantalum (BSiTa) ternary hybrid phenolic aerogel (BSiTa-PA) that exhibits exceptional thermal insulation, mechanical strength, and electromagnetic interference (EMI) shielding properties. The aerogel is prepared through a rapid method involving sol-gel and ambient pressure drying processes, integrating organic, inorganic, and metal elements. Key findings include: 1. **Thermal Insulation and Mechanical Strength**: BSiTa-PA demonstrates low thermal conductivity (49.6 mW m⁻¹ K⁻¹) and high mechanical strength (39.4 kN·m kg⁻¹), making it suitable for extreme thermal environments. 2. **EMI Shielding**: After thermal ablation, the aerogel transforms into a carbon aerogel with high EMI shielding efficiency (31.6 dB) and load-carrying capacity (272.8 kN·m kg⁻¹). 3. **Microstructural Evolution**: The aerogel's microstructure evolves during ablation, forming small graphite domains, good ceramic structures, and abundant nanopores, which contribute to its excellent ablative resistance and EMI shielding. 4. **Structural Analysis**: XRD, SAXS, XPS, Raman spectroscopy, and MIP analyses reveal the transformation of the aerogel into a hard carbon structure with turbostratic properties, enhancing its mechanical robustness and EMI shielding performance. 5. **Conclusion**: The developed BSiTa-PA aerogel offers a promising solution for advanced thermal protection and EMI shielding in aerospace applications, laying the foundation for the advancement of multifunctional materials in extreme environments.