The paper explores the relationship between quasinormal modes (QNMs) and the shadows of rotating regular black holes (RBHs). The authors extend the known correspondence between QNMs and the shadows of spherically symmetric black holes to more general rotating spacetimes. They argue that this extension holds under conditions related to the separability of the Hamilton-Jacobi equation for null geodesics and the Klein-Gordon equation. The metrics obtained using the Newman-Janis algorithm are shown to satisfy these conditions, provided certain mathematical requirements are met. The authors explicitly verify this correspondence for rotating Bardeen and Hayward RBHs, demonstrating that the eikonal QNM-shadow radius correspondence holds for a wide range of axisymmetric spacetimes beyond Kerr. This finding paves the way for potential strong-field multi-messenger tests of fundamental physics, combining gravitational wave spectroscopy and Very Long Baseline Interferometry (VLBI) imaging to better understand black holes.The paper explores the relationship between quasinormal modes (QNMs) and the shadows of rotating regular black holes (RBHs). The authors extend the known correspondence between QNMs and the shadows of spherically symmetric black holes to more general rotating spacetimes. They argue that this extension holds under conditions related to the separability of the Hamilton-Jacobi equation for null geodesics and the Klein-Gordon equation. The metrics obtained using the Newman-Janis algorithm are shown to satisfy these conditions, provided certain mathematical requirements are met. The authors explicitly verify this correspondence for rotating Bardeen and Hayward RBHs, demonstrating that the eikonal QNM-shadow radius correspondence holds for a wide range of axisymmetric spacetimes beyond Kerr. This finding paves the way for potential strong-field multi-messenger tests of fundamental physics, combining gravitational wave spectroscopy and Very Long Baseline Interferometry (VLBI) imaging to better understand black holes.