<p>Accurate determination of elastic properties at the structural scale remains a key challenge in the design of composite wrapped pipes. This work introduces a non-destructive, pipe-level identification methodology that determines the full in-plane orthotropic elastic response of multi-material composite pipes using only axial loading and internal pressure tests. A trace-based stiffness formulation is developed for pipes composed of a PVC liner and a fiber-reinforced polymer composite wrap, enabling direct identification of axial and hoop Young’s modulus and the associated Poisson’s ratios from pipe level measurements. The in-plane shear modulus is subsequently inferred from the invariant trace of the reduced stiffness matrix (Tsai’s modulus), eliminating the need for torsion testing or coupon extraction. The results provide structural scale validation that the trace-based formulation, originally developed for unidirectional carbon fiber composites, can be successfully extended to woven glass fiber reinforced polymer (GFRP) composites. Four nominally identical pipes were tested under axial tension, axial compression, and internal pressure, with three repeated runs per loading mode. Despite identical constituents and processing conditions, measurable pipe to pipe variability was observed. These findings demonstrate that reliance on unidirectional ply data or coupon level surrogates is insufficient for reliable structural prediction of multilayer composite pipes and that pipe-level characterization is required. Finite element simulations using the identified properties reproduced the measured axial and hoop surface strains within the experimental 95% confidence bands for all load cases. The proposed methodology reduces experimental complexity and cost while providing elastic properties directly applicable to structural models of composite pipe systems trace-based.</p>