The growing adoption of cryptocurrency in sub-Saharan Africa presents both opportunities for financial inclusion and risks for national security. While global studies highlight how extremist groups exploit digital assets, little is known about how African organisations such as Boko Haram, ISWAP, and Al-Shabaab adapt these technologies within fragile institutional settings. The study adopted a mixed-methods design, combining surveys of 103 respondents (67 in Nigeria and 36 in Kenya) with 11 expert interviews. Analysis was guided by Social Network Theory, which explains decentralised networks of financial exchange, and Realism, which highlights state vulnerabilities in fragile governance contexts. Findings reveal that terrorist organisations in both countries rely heavily on peer-to-peer transfers, unregulated exchanges, and informal brokers. Respondents also noted limited use of privacy coins, emerging darknet procurement, and, in Kenya, the growing integration of mobile money with crypto wallets. The evidence shows that illicit actors exploit weak enforcement rather than advanced technologies. Terrorism financing in Nigeria and Kenya mirrors global practices but is shaped by local vulnerabilities, including reliance on informal brokerage and mobile–crypto convergence. Institutional weakness, not technological sophistication, emerges as the decisive factor enabling illicit financing. The study reframes terrorism financing in Africa as a hybrid phenomenon shaped by fragile enforcement systems, extends Social Network Theory to socio-technical infrastructures, and challenges Realism’s assumption of coherent state sovereignty. Governments should strengthen blockchain forensics, regulate exchanges, secure mobile–crypto platforms, and promote cross-border cooperation while safeguarding financial inclusion.