Spacetime as a Relational Manifold develops a relation‑first account in which spacetime is not a four‑dimensional container but the joint expression of two fundamental relational operators: orientation (time) and separation (space). The paper argues that neither space nor time is primitive. Instead, both emerge from the dynamics of a generative relational field. Time arises from the coherence of orientation across updates; space arises from the stabilization of persistent non‑coincidence. When these operators cohere, they generate a unified manifold whose structure reflects the system’s available relational degrees of freedom.The paper introduces the Universal Triad—generation, boundary, and expression—as the minimal structure required for dimensionality to appear and for geometry to stabilize. Curvature is interpreted not as deformation of a background metric but as a pattern of constraints on allowable relational transformations. Expansion is explained as the increase of generative bandwidth, represented by the radius of the relational hypersphere, rather than as motion into a pre‑existing void. This framework dissolves the container model, resolves the problem of time, and grounds spacetime structure in the internal dynamics of relation itself.