Background: Cross-border crime poses significant threats to national security and economic development in Sub-Saharan Africa. The Ekok-Nfum border between Cameroon and Nigeria represents a critical case study, where porous borders facilitate illicit trade, human trafficking, and arms smuggling despite existing security protocols. This study examines the mechanisms through which cross-border crime can be mitigated to permit legitimate transnational trade. Methods: A descriptive survey design was employed using stratified and cluster sampling techniques. Data were collected from 300 respondents, including border officials, traders, and security personnel, through structured questionnaires and semi-structured interviews. The study utilised the theories of Transnationalism, Regulation, and Ecological Systems as analytical frameworks. Data analysis employed descriptive statistics and chi-square hypothesis testing. Results: Findings indicate that cross-border crime significantly threatens transnational security (χ² = 157.255, p < 0.001), with 69% of respondents confirming the severity of threats, including arms trafficking, drug smuggling, and human trafficking. Customs officials play a significant role in mitigating insecurity (χ² = 60.017, p < 0.001), though their effectiveness is constrained by inadequate resources, corruption, and conflicting local and national taxation interests. Trans-governmental enforcement networks are essential for cross-border collaboration (χ² = 50.354, p < 0.001), with informal cooperation mechanisms proving more effective than formal treaty-based approaches. Conclusion: The study recommends enhanced customs autonomy, community-based border development, and informal trans-governmental enforcement networks to mitigate crime while facilitating legitimate trade. Economic development in border regions remains crucial for reducing criminal incentives.