<p>This study aims to assess the fatigue reliability characteristics of in-service pipes under the random stress loads by determining the fatigue life for corrosion-induced degradation of monotonic and cyclic properties in API X65 steel pipe. Offshore pipeline fatigue failures are associated with random loading conditions and varying material properties caused by corrosive environments, which raise limitations in fatigue life predictions using deterministic methods, necessitating that fatigue evaluation be regarded as a stochastic process. Random internal pressure time series data for five years from in-service offshore pipelines were used to characterise the load uncertainties in biaxial stresses, and material mechanical properties in corrosive environments were characterised and used in fatigue durability assessment using three stress life models to assess the fatigue life prediction. The results for fatigue life data over five years were further used in fatigue reliability evaluation to calculate an appropriate distribution, reliability, mean cycles to failure, and hazard rate. Experimental results indicated that corrosion pitting reduced material tensile strength by 14% and cyclic strength coefficient by 8.3% while the fatigue endurance limit decreased from 292 to 265&#xa0;MPa. The Weibull distribution was deemed appropriate for modelling the probabilistic fatigue life distribution to evaluate reliability ranging from 0.53 to 0.55. The estimated stochastic fatigue life ranged from 1.03 × 10⁹ to 3.3 × 10¹⁰ mean cycles to failure. The reliability index for the predicted life of random operational stresses was calculated as 3.53, 2.21, and 2.02 under three stress-life models. Therefore, the data-driven fatigue reliability for offshore pipelines is modelled to include the effects of mean stresses and degradation in mechanical properties of material in fatigue life prediction related to the corrosion fatigue mechanism.</p>