Concrete structures in offshore oil and gas infrastructure are increasingly exposed to aggressive environments containing chlorides, sulfates, and acidic media, resulting in significant durability challenges. This study investigates the mechanical and durability performance of concrete incorporating ternary blends of Glass Powder (GP), Rice Husk Ash (RHA), and Metakaolin (MK) as supplementary cementitious materials (SCMs). Six concrete mixtures with 0–30% total SCM replacement were evaluated for compressive strength and durability properties, including water absorption, acid and sulfate resistance, rapid chloride penetration (RCPT), and sorptivity, at curing ages of 7, 28, 56, and 90 days. The mixture containing a 20% ternary replacement (6.6% each of GP, RHA, and MK) exhibited optimal performance, achieving a compressive strength of 38.2 MPa at 90 days while significantly reducing permeability and degradation under aggressive exposure conditions. Response Surface Methodology (RSM) based on Central Composite Design (CCD) was employed not only to model performance responses but also to identify an optimized durability-oriented binder composition, with regression models showing strong predictive accuracy (R² ≥ 0.93) and a high desirability index of 0.945.Unlike existing studies that predominantly focus on binary SCM systems or isolated durability indicators, this research presents a comprehensive experimental and statistical evaluation of a ternary GP-RHA-MK concrete system under multiple aggressive offshore exposure conditions. The combined application of systematic durability testing and multi-objective RSM optimization establishes a novel durability-driven framework for proportioning ternary SCM concretes tailored to offshore oil and gas infrastructure. The findings demonstrate that such optimized ternary systems can simultaneously enhance performance, durability, and sustainability while promoting the effective reuse of agro-industrial and glass waste.