Aim
To describe transitions in smoking status and their determining factors among nursing students between baseline (2015–2016) and follow-up (2018–2019).

Design
Observational prospective longitudinal study of 4381 nursing students in Catalonia (Spain).

Methods
We examined transitions in smoking status from: (i) current smokers to recent quitters, (ii) never smokers to new smokers and (iii) former smokers to quitters who relapsed. We fitted logistic regression models to assess the predictors of quitting smoking.

Results
The proportion of current smokers decreased from 29.7% at baseline to 23.6% at follow-up, with a cumulative incidence rate of quitting of 28.3% during follow-up. Nondaily smokers were more likely to quit than daily smokers. Of those who were never smokers at baseline, 4.6% were smokers at follow-up, and 23.2% of former smokers at baseline had relapsed at follow-up.

Conclusions
Nondaily smokers were more likely to have quit smoking at follow-up among this cohort of nursing students. The early implementation of a comprehensive tobacco control program that includes tobacco-free campus policies, tobacco prevention interventions and cessation support during college years may decrease tobacco use among nursing students.

Impact
Nursing students' tobacco use is concerning, as they are the future workforce of nurses who have a key role in tobacco product use prevention and cessation. During college years, nursing students have a greater likelihood of experimenting with several smoking status changes as well as to consolidate smoking behaviors. This is the first longitudinal study to highlight the factors associated with quitting smoking among a cohort of Spanish nursing students. Being a nondaily smoker at baseline predicted quitting at follow-up. Our findings support the early implementation of a comprehensive tobacco control program that includes tobacco-free campus policies, tobacco prevention interventions and tobacco cessation support during college years to decrease tobacco product use prevalence among nursing students.

Reporting Method
We have adhered to STROBE guidelines. No Patient or Public Contribution. This observational study has not been registered.