Objectives To investigate the incidence and characteristics of acute time-loss injuries in Finnish junior floorball league players.

Design Prospective cohort study with 3-year follow-up.

Methods One hundred and eighty-six female and male players (mean age 16.6 ± 1.4) took part in the follow-up study (2011–2014). The training hours and games were recorded on a team diary. Floorball related acute injuries were registered and verified by a research physician. The injury incidence was expressed as the number of injuries per 1000 h of exposure. Incidence rate was calculated separately for games and practices, and for males and females.

Results One hundred and forty-four acute time-loss injuries occurred. Injury incidence was 26.87 (95% CI 20.10–33.63) in junior league games, and 1.25 (95% CI 0.99–1.52) in team practices. Female players had significantly higher game injury rate (IRR 1.88, 1.12–3.19) and joint/ligament injury rate (IRR 1.70, 1.07–2.73) compared to males. Eighty-one percent of the injuries affected the lower limbs. The ankle (37%), knee (18%), and thigh (14%) were the most commonly injured body sites. More than half of injuries involved joint or ligaments (54%). Twenty-six percent of the injuries were severe causing more than 28 days absence from sports. Eight anterior cruciate ligament ruptures of the knee occurred among seven female players.

Conclusion The study revealed that risk of ankle and knee ligament injuries is high in adolescent floorball, specifically among female players.