Objective: Vaccination coverage (VC) among young adults is not routinely measured. The Defense and Citizenship Day (JDC) is mandatory and targets young people aged 16 to 18. The objective of this study was to estimate VC against measles, meningococcal C infections, hepatitis B, and human papillomavirus (HPV) infections, and to assess VC for the pertussis booster between ages 11 and 13 among JDC participants born between 1997 and 2000. The secondary objective was to describe the dynamics of catch-up vaccination. Method: The survey was conducted over one week each year from 2015 to 2018 at the Rennes National Service Center. Vaccination coverage data were entered on-site from health records (CS). The number of doses and dates of administration were collected for each vaccine. A person was considered properly vaccinated if they had received the number of doses recommended by the vaccination schedule on the day of the JDC. Results: Of the 1,633 young people present, 1,360 (83%) had brought their health record or an equivalent document, and among them, 1,184 were born between 1997 and 2000. Depending on the birth cohort, vaccination coverage ranged from 92.6% to 96.9% for measles, from 34.6% to 51.5% for meningitis C, from 43.5% to 49.1% for hepatitis B, from 58.8% to 73.4% for pertussis (ages 11–13), and from 29.3% to 35.6% for vaccination against human papillomavirus infections in young girls. The proportion of adolescents vaccinated as part of the catch-up campaign changed little. Discussion and Conclusion: Our survey yielded results similar to those provided by other age-specific data sources. The recruitment site helped minimize selection bias in an age group where it is difficult to estimate vaccination coverage. The methodology allows for a description of the dynamics of catch-up vaccination. This survey enabled the monitoring of vaccination coverage among adolescents in Ille-et-Vilaine using high-quality indicators. It shows that significant efforts will be required regarding catch-up vaccination and the promotion of adolescent vaccination, particularly against meningitis C and human papillomavirus infections.