This report examines the economic effectiveness of integrated outreach vaccination services to improve childhood immunization rates in Eswatini, currently below the Global Vaccine Action Plan target of 90%. The study conducted by Eswatini’s Ministry of Health and UNICEF compared the cost-effectiveness of ad hoc vaccination campaigns versus integrated outreach services. The analysis distinguished between the business-as-usual scenario (nationwide campaigns at fixed sites) and the intervention scenario (mobile outreach for routine vaccinations and health services). Excluding vaccine costs, the HPV campaign had the highest delivery cost per child vaccinated (USD 17.3) and the measles campaign was the lowest (USD 3.7). The periodic intensification routine immunisation catch-up campaign costs USD 5.0 per child. Public health unit outreach services showed costs ranging from USD 3.5 to USD 23.5, averaging USD 6.1, while the NGO integrated outreach, offering additional services and electronic tracking, costs USD 9.2 per child. The intervention services were more cost-effective than the HPV campaign but less so than the measles campaign. The NGO outreach, despite higher costs, provided broader benefits, particularly to marginalized populations.