Rotavirus Efficacy and Safety Trial (REST) enrolled nearly 70,000 infants, of whom more than 23,000 were from Finland. REST determined the efficacy of the pentavalent rotavirus vaccine (RV5) against rotavirus-related hospitalisations and emergency department (ED) visits in the first year after vaccination. Finnish infants initially in REST transitioned into the Finnish Extension Study (FES), where they were followed for rotavirus-related hospitalisations and ED visits through their second year of life and beyond. FES identified 150 (31%) additional rotavirus gastroenteritis (RVGE) cases beyond those identified in REST in the Finnish participants. Overall, RV5 reduced RVGE hospitalisations and ED visits, regardless of the rotavirus serotype, by 93.8% (95% confidence interval [CI]: 90.8-95.9%) for up to 3.1 years following the last vaccine dose. Vaccine efficacy against combined hospitalisations and ED visits between ages 4 months to 11 months, 12 months to 23 months, and 24 months to 35 months was 93.9% (95% CI: 89.1-96.9%), 94.4% (95% CI: 90.2-97.0%), and 85.9% (95% CI: 51.6-97.2%), respectively. The reduction of hospitalisations and ED visits due to any acute gastroenteritis, rotavirus or not, was 62.4% (95% CI: 57.6-66.6%) over the entire follow-up period. The results from FES confirm that RV5 induces high and sustained protection against rotavirus-related hospitalisations and ED visits, and has a very substantial impact on all gastroenteritis-related hospitalisations and ED visits into the third year of life in Finnish children.