<p>Silicon carbide (SiC) porous materials possess exceptional electromagnetic wave absorption capabilities. In recent years, various SiC-based wave-absorbing materials have been developed. However, their inherent brittleness restricts their applications, posing an ongoing challenge in balancing wave absorption with mechanical performance. Herein, a templated chemical vapor deposition strategy was employed to fabricate hierarchical hollow SiC micro/nanofiber sponges (HHSMSs). The directional growth and orderly arrangement of SiC nanorods on the template fibers construct a micro–nano-structured SiC shell layer. By controlling the reaction time, the thickness of this shell layer can be tuned between 0.4 and 3.1 µm. Moreover, during the deposition process, an amorphous SiO_x structure tends to form on the outer surface of the fibers. Owing to this amorphous SiO_x structure, HHSMSs demonstrate excellent flexibility and elasticity, allowing them to be bent by 180° and compressed by 60%. In addition, the hierarchical hollow structure enhances impedance matching, resulting in superior electromagnetic wave absorption with a minimum reflection loss of −51.8 dB and an ultra-wide effective absorption bandwidth (EAB) of 8.6 GHz. These properties highlight the potential of these flexible, broadband-absorbing sponges for stealth and electromagnetic interference shielding in high-temperature environments.</p> Graphical abstract <p></p>