Nuclear fusion offers the promise of a clean, safe, and virtually limitless energy source, although it demands the development of advanced materials capable of withstanding extreme thermal, mechanical, and irradiation environments. In this regard, carbon-based materials have emerged as critical candidates for both plasma-facing and structural applications in fusion reactors. Among these, carbon fiber-reinforced carbon composites (CFCs) have gained excellent maturity with advances in architecture—such as high-density 1D C–C composite and joining technologies enabling reliable performance under operating conditions. On the other hand, silicon carbide fiber-reinforced composites (SiC/SiC f ) have shown great potential as structural and functional materials, particularly as flow channel inserts in fusion blanket systems. These composites exhibit exceptional irradiation tolerance, thermal stability, and chemical compatibility at elevated temperatures. Nuclear-grade SiC/SiC f produced through techniques such as chemical vapor infiltration (CVI) and nano-infiltration and transient eutectic-phase (NITE) processing offer engineered microstructures and robust interphases. Advances in joining methods have further mitigated issues related to thermal expansion mismatch in complex assemblies. However, common challenges such as neutron-induced transmutation, helium/tritium penetration and the assembly of fusion-relevant components still remain. This chapter reviews the current state and future prospects of carbon-based materials in fusion applications, emphasizing their pivotal role in the realization of next-generation fusion energy systems.