<p>A novel approach has been developed to simulate hygrothermal environments in an infinite, homogeneous, isotropic hollow cylinder where heat and moisture are either generated or absorbed. This model is based on the three-phase-lag-hygro-thermal theory of hygrothermoelasticity, which includes non-Fourier and non-Fick effects. It incorporates heat and moisture fluxes, memory-dependent derivatives (MDD), and a non-local Klein–Gordon (KG) system. The research focuses on analyzing the hygrothermoelastic properties of a homogeneous cylinder with internal sources subject to varying boundary flux conditions. Using the Laplace transform, the mathematical model is solved in the transformed domain, and numerical inversion is employed to obtain physical characteristics such as displacement components and hygrothermal stresses in the physical domain. Graphical representations are generated using Mathematica software to illustrate these effects. This work introduces a unified hygrothermoelastic framework that integrates TPL theory, MDD, and non‑local KG elasticity. By simultaneously accounting for finite hygrothermal wave speeds, time‑dependent memory hysteresis, and spatial nonlocality, the model delivers more realistic stress predictions in hollow cylinders than fractional or local formulations, establishing a new benchmark for pipeline design in hygrothermal environments. </p>