Results: since 2016, the number of sports clubs with an outdoor sfp increased from 0.3% to 26.4%. field hockey [or compared to football 6.00 95% ci 4.46-8.07] and korfball clubs [or 6.65 95% ci 4.98-8.87] and clubs with many (youth) members [or 8.75 95% ci 6.20-2.35] were more likely to be smoke-free. sfps spread from the most urbanized to less urbanized municipalities, which could mostly be attributed to sports clubs’ characteristics. a higher density of smoke-free sports clubs within municipalities was associated with an increased incidence of new sfps in the following year. conclusions: outdoor sfps at sports clubs in the netherlands diffused across horizontal and hierarchical lines. national strategies for smoke-free sports should monitor clubs that are more likely to stay behind, such as football and tennis clubs, smaller clubs, and clubs in less urbanized areas