<p>Coral reef limestone is a highly porous and anisotropic sedimentary rock that is widely distributed on continental shelves and in deep-sea regions. Thus, characterizing fluid flow through coral reef limestone is very crucial for many engineering applications in coastal and offshore areas. In this paper, we develop a combined experimental and numerical study of the flow properties of anisotropic coral reef limestone with coarse or fine pore structures. First, X-ray computed tomography (CT) was used to reconstruct the detailed three-dimensional pore networks of coral reef limestone samples, whose flow properties were experimentally measured based on constant head tests. The reconstructed pore networks were then used for computational fluid dynamics (CFD) simulations to model fluid flow. The results from the experiments and simulations show that the hydraulic conductivity of coarse pore coral reef limestone exhibits a clear power-law relationship with the direction of coral growth lines. The hydraulic conductivity of coarse pore coral reef limestone can vary over one order of magnitude depending on the direction, while the permeability variation of fine pore reef limestone is much narrower. Water flow within the coral reef limestone displays non-Darcy seepage behavior, and the relationship of flow rate versus pressure aligns well with Forchheimer's equation. Additionally, the analysis of water flow characteristics within the pore network of the coral reef limestone indicates that the throat Reynolds number is very low under low pressure, indicating a predominantly laminar flow regime. However, as pressure increases, the throat Reynolds number rapidly rises, with turbulent flow developed locally. The findings of this study provide valuable insights for understanding and quantifying fluid flow in coral reef limestone formations.</p>