Abstract Aims Alcohol intake is a well-established risk factor for atrial fibrillation (AF). However, evidence on the effects of changes in alcohol intake to primary AF prevention is sparse. The aim of this study was to examine the association between 5-year changes in alcohol intake and the risk of incident AF. Methods and results This study was based on the Danish cohort study Diet, Cancer and Health. Lifestyle factors were assessed using questionnaires at a recruitment research examination and a second examination 5 years later. Diagnoses of AF and comorbidities were retrieved from the Danish National Patient Registry. 43 758 participants without prior AF were included. The median age was 61 (25th–75th percentile 58–66) years and 54% were female. Over a median follow-up time of 15.7 years, 5312 participants had incident AF (incidence rate 8.6/1000 person-years). Compared with stable intake, increases in alcohol intake to ≥21 drinks/week from ≤6.9 drinks/week (HR: 1.38, 95% CI: 1.09–1.72) or 14–20.9 drinks/week (HR: 1.27, 95% CI: 1.01–1.59) at baseline were associated with a higher risk of AF. In contrast, we did not observe a statistically significant association between reductions in alcohol intake and the risk of AF. Conclusion A 5-year increase in alcohol intake was associated with a greater risk of AF compared with a stable low/moderate intake.