Immunization serves as a cost-effective shield against vaccine-preventable diseases, promoting population health and sustainable prosperity. This study aimed to determine vaccination coverage and assess the timeliness of vaccination (BCG, PENTA1, and measles vaccines) among children aged 12 to 23 months in the wards of Calabar South Local Government Area (LGA) in Cross River State. A community-based cross-sectional descriptive design was employed, with the number of children sampled being 460 to account for non-response and design. Information about children were obtained through interviews with proxy caregivers. Data analysis was performed using SPSS version 25.0. Ethical approval was obtained from the CRS Ministry of Health. There were 190 male children (41.3%) and 275 female children (58.7%) in the study. The age group of 12-15 months (55.2%) represents the largest category. The overall vaccination coverage was 88.3%, varying across wards (100% in ward 4, followed by 96.1% in ward 8, then 96% in ward 5, 91.6% in ward 12, and 80.8% in ward 11). The proportion of overall timely vaccination was 71.5%, with PENTA1 having the highest timeliness (88.3%). The proportions of timely vaccination for BCG and PENTA1 were highest in ward 4, followed by ward 5, but lowest in ward 11. Timeliness for all vaccines was also highest in ward 4, followed by ward 12, then ward 5, ward 8 and ward 11. Vaccination coverage and timeliness differed between locations, highlighting the need for Government interventions to be context-specific, addressing challenges within different ward locations rather than applying a one-size-fits-all approach.