This study investigates the structural behavior of timber-to-timber composite beams connected using welded-through wood dowels, a novel fastening technique that enhances compatibility and sustainability compared to traditional metal connectors. Full-scale two-layer timber beams were fabricated and subjected to four-point bending tests to assess flexural performance, stiffness, and load distribution. Each specimen consisted of solid wood boards joined with 56 welded dowels, evenly spaced along the beam span. A corresponding finite element model was developed using Abaqus, exploiting geometric symmetry to improve computational efficiency. Two models were compared: a dowel-connected beam and an unjointed reference beam. Orthotropic material properties were assigned to simulate the anisotropic behavior of spruce timber, with fictitious vertical dowels adjusted for oblique orientation through local material rotation. The model incorporated detailed contact interactions and boundary conditions to replicate the physical test setup accurately. Results demonstrate that welded-through dowels significantly enhance shear transfer between timber layers, increasing global stiffness and improving structural integrity. Load–deflection curves from both experimental and numerical models confirm the effectiveness of the dowel system in achieving partial to near-full composite action. These findings suggest that welded-through dowels are a viable solution for sustainable, high-performance timber composites in structural applications.