Transborder crimes are criminal activities that transverse borders of two or more countries. Notable crimes that flourish across Nigerian’s borders are illicit drug trafficking, Terrorism, proliferation of small arms and light weapons ( SALWs), Human trafficking, internet fraud, oil theft, smuggling of goods among others. All these activities have precipitated security and economic complications across West Africa sub region. The 2022 Global peace Index ranked Nigeria 143 among 163 independent Nations and Territories according to the level of peacefulness while Cato Institute a Washington DC based public policy research organization rated Nigeria as the most unsafe place on earth after Iraq. This phenomenal rise of criminal ratings of Nigeria had attracted local and international attentions of scholars, policy makers and governments. Thus, this study investigates Transborders crimes in Nigeria using qualitative research methodology by reviewing the existing literature and conducting in-depth interviews of 85 informants selected randomly from government establishments and among stakeholders in Nigeria. The study relied on rational choice theory and behavioural theory as theoretical frameworks. The study revealed that Transborder crimes thrive across the West African nations because of many factors which include but not limited to the implementation of ECOWAS protocol on free movement of persons and goods, porous borders, youth unemployment, poverty, poorly trained and ill-equipped security personnel, corruption, poor inter-agency coordination and collaboration. The study concluded that despite various measures by the Nigerian government and International organizations like ECOWAS, UNO, AU to checkmate the scourge, the desired results have not been achieved. The study therefore recommended effective border monitoring and management, job creation, community policing initiative, increased military actions and surveillance, among others as panacea to Transborder crimes detection, reduction and prevention.