Purpose: Type II endoleaks (T2EL) are common after EVAR. Evidence guiding patient selection and predictors of durable sac stabilisation is limited. This study describes the contemporary Western Australian experience of T2EL intervention, focusing on durability and clinical outcomes. Methodology: Retrospective cohort study across three vascular centres (2014–2024). Demographic, anatomical, procedural and follow‑up data were extracted from electronic medical/imaging records. Primary outcomes: freedom from aneurysm sac growth >5 mm and freedom from aneurysm‑related events. Secondary outcomes: technical success, peri‑procedural complications, reintervention and survival. Results: Eighty patients underwent T2EL intervention (median age 74, 85% male). T2ELs were diagnosed early and late post EVAR: 65.8% within 12 months, 12.3% between 13–36 months, 13.7% between 37–60 months, and 8.2% beyond 60 months (non‑unimodal distribution: Hartigan’s dip test D = 0.089, p < 0.001). Sac expansion was the primary indication for treatment (80%). Technical success was achieved in 61%. Peri‑procedural complications were uncommon (≤9%). At median follow‑up of 43 months, 55.7% achieved freedom from >5 mm sac growth. Cumulative incidence freedom from aneurysm‑related events was 84.9% at 5 years. Reintervention occurred in 41%. On Firth multivariable analysis, reintervention was the only independent predictor of freedom from sac growth (OR 0.30, 95% CI 0.10–0.90). Kaplan-Meier survival at 5 years was 59%. No covariates were independently associated with mortality on Cox regression. Conclusions: Clinically significant T2ELs were diagnosed early and late supporting ongoing surveillance. T2EL interventions were safe, with low complication and aneurysm‑related event rates, but demonstrated modest sac stabilisation, over 40% requiring reintervention. Reintervention was the only factor associated with sac stability, supporting careful patient selection and counselling regarding durability.