Abstract Background Barriers and facilitators to physical activity in inflammatory arthritis can be assessed through the Inflammatory arthritis FAcilitators and Barriers (IFAB) questionnaire. The objective was to measure the correlation between IFAB and self-reported physical activity levels. Methods This was an international, multicentric, cross-sectional study in 2019–20. Consecutive spondyloarthritis (axSpA), rheumatoid arthritis (RA) or psoriatic arthritis (PsA) patients completed the 10-item IFAB, which ranges from − 70 to 70 with lower scores indicating more barriers. Physical activity was measured by the IPAQ-S questionnaire, steps per day collected by smartphone, and psychological readiness to change by stages of behaviour change. Spearman correlations and multivariable linear regression were calculated. Results Of 245 patients included, 150 were analysed: 69 (46%) axSpA, 63 (42%) RA, 18 (12%) PsA. Mean age was 48.6 years (standard deviation, SD 17.1), mean disease duration 11.7 (10.1) years and 60% were women. Barriers to physical activity were moderate: mean IFAB, 6 (SD 19.2); 39 (26%) patients scored less than − 5, corresponding to significant barriers. The mean physical activity was 2837 (SD 2668, median 1784) MET-minutes per week. The IPAQ-S questionnaire was correlated with the IFAB (rho 0.28, p < 0.001), as well as the stage of behaviour change (rho 0.35, p < 0.001) though not with steps per day. Multivariable analyses were confirmatory. Conclusion Perceived barriers and facilitators to physical activity were correlated with physical activity, indicating that targeting patients with high barriers and low facilitators to physical activity could be an effective option to improve physical activity levels. Trial registration ClinicalTrial NCT04426747 . Registered 11 June 2020 - Retrospectively registered.