Abstract Background The third-generation laser balloon (LB3) is equipped with an ultra-compliant balloon and a motor-driven laser generator, which contribute to durable and gapless isolated lesion creation. However, the efficacy of wide-area pulmonary vein (PV) isolation (PVI) using LB3 remains to be elucidated. Purpose This study aims to investigate efficacy of wide-area PVI using LB3. Methods This is a single-center retrospective study. Patients with atrial fibrillation (AF) who underwent LB3 ablation during the period from August 2021 to June 2022 were enrolled. All PVs were electrically isolated only by LB3. After initial circular ablation, LB3 was inflated to a larger size at each PV, and the isolation area was extended. After ablation, voltage maps of the left atrium were obtained by high-resolution mapping catheters to evaluate isolation areas (<0.1mV). Follow-up included a 12-lead electrocardiogram, Holter monitoring, and/or pacemaker/implantable cardioverter-defibrillator interrogation. The efficacy endpoint was defined as freedom from atrial tachyarrhythmia (ATa) between months 3 and 12. Results Forty-four patients with paroxysmal AF and 34 with persistent AF (mean arrhythmia duration 12.4 months, range 1–60 months) were included. First pass isolation was achieved in 90.6% (280/309) of PVs. The total laser application time was 24.1±6.4 minutes, and the total delivered energy was 15.3±3.2 kJ. The isolation area at the left- and right-sided PV antrum were 14.2±1.8 and 19.5±1.1 cm², respectively. At the end of the 12 months of follow-up, the freedom from ATa was 78.2% in patients with paroxysmal AF and 78.0% in persistent AF, which indicates ATa free survival at one year was similar in both groups (P=0.91). Conclusions Wide-area PVI using LB3 may lead to favorable outcomes in patients with AF.Fluoroscopic and endoscopic imageKaplan-Meier curves and voltage map