Introduction: Cervical cancer is the second highest cause of cancer-related deaths in women in Nigeria. Human papillomavirus (HPV) infection, particularly types 16 and 18, causes 95% of this burden. In 2023, Nigeria first incorporated the HPV vaccine into its Expanded Program on Immunization. While the federal and state governments led the program, community and partners quickly addressed gaps. This study estimated the financial costs of HPV vaccine introduction in Nigeria, examining Bayelsa (southern) and Taraba (northern) states. Methods: The study employed a mixed-methods approach, combining quantitative (days worked and doses administered) and qualitative (stakeholders’ insights) data. Results: The two states achieved high coverage (Bayelsa, 74%; Taraba, 78%), close to the ambitious 80% national target. The total financial cost per fully vaccinated girl was also similar, at $6.04 (Bayelsa) and $6.02 (Taraba). Antigen cost $4.99 (82.6% to 83.0%) per girl and operations cost $1.05 (17.4%) and $1.03 (17.0%) in the respective states. Transportation, logistics and data tool costs were the largest proportion of the operational cost (Bayelsa, 38.1%; 39.0%, Taraba). Service delivery (Bayelsa, 22.2%; Taraba, 22.4%), and the advocacy, communication, and social mobilization activities (ACSM) costs (Bayelsa, 20.0%; Taraba, 20.5%) also represented notable operational cost drivers. Vaccine procurement costs substantially exceeded operational costs in both states. Discussion: The states’ initial intensive campaign strategy with community and partners’ continual collaboration in planning and implementation proved effective in quickly achieving high coverage. These states’ success in introducing HPV vaccine through a campaign strategy can serve as a useful model for other countries.