Purpose: A stable contact force (CF) is correlated with more effective radiofrequency ablation (RFA) lesions and long-term procedural outcomes. Efforts to improve catheter stability include jet ventilation, pacing, steerable sheaths, and CF sensing ablation catheters. This study compares CF stability and effective RF lesions between two commercially available steerable sheaths. Methods: Thirty patients underwent first time RFA at a single center using the Agilis NxT or SureFlex Steerable Sheath. High power short duration RFA was utilized targeting a 10Ω drop. Sheath performance was assessed for the entire procedure and around each pulmonary vein (PV) in terms of mean CF, CF variability, RF time per lesion, and inefficient contact lesions (defined as lesions with CF < 5g for at least 10% of the RF delivery time). Results: Operator-targeted mean CF was achieved using both sheaths; however, overall CF variability was 12.8% lower using the SureFlex sheath (p = 0.08). CF variability was generally 16% greater in the right PVs than the left PVs (p = 0.001), but trended lower with the SureFlex sheath. There were 8% more inefficient contact lesions using Agilis as compared to SureFlex (p = 0.035), especially in the right inferior PV (p = 0.009). RF time per lesion was on average 12% (1.4s) shorter using SureFlex than Agilis (p < 0.05). Conclusion: Choice of steerable sheath may affect catheter stability and potential lesion quality, especially in the right PVs.