Abstract: Seepage critically influences the design, construction and operational safety of tunnels. Their excavation induces transient seepage fields that mutually interact with those of adjacent pressure relief tunnels. To address the transient seepage coupling mechanism of twin shallow buried parallel tunnels, a two-dimensional plane strain analytical model is developed. For a single shallow circular tunnel, the semi-infinite seepage domain is mapped to an annular region by using the conformal transformation, and the transient seepage fields are derived by integrating the superposition principle and variable separation method. Subsequently, the Schwarz iteration method is employed to construct the iterative algorithm for dual tunnel transient seepage coupling, achieving temporal superposition through dynamic boundary coupling and spatiotemporal discretization. The validations against numerical simulations and published data confirm the accuracy and computational efficiency of the solution. This analytical framework provides a theoretical basis for deciphering the transient seepage interactions in tunnel clusters under complex geological conditions, offering critical insights for seepage risk mitigation in deep underground engineering.