Mudmat foundations are primary choice for subsea structures due to their easiness during installation and simple for design. These mudmats are usually rectangular shaped steel structures fitted with vertical skirt plates. The mudmat foundation design usually assumes that the ground surface is flat, but in certain instances, such as seabed with sand wave features, the ground surface is uneven. In the end, the foundation surface does not fully contact with the ground surface, leading to the initial design assumption not being met and the bearing capacity of the foundation being reduced. Seabed preparation such as jetting is often carried out to flatten the seabed. However, the outcome of such operation is often unpredictable, and the seabed surface may remain uneven. This is particularly problematic in carbonate soils which are known to be brittle and lose its shear strength under repeated loading conditions. This paper discusses a practical design approach for addressing the challenge of a mudmat foundation resting on an undulating seabed using a case study where a mudmat foundation rest on sand wave carbonate soil. The mitigation measures prior to the installation of mudmat have also been discussed, including seabed survey and seabed preparation and required instrumentation. Subsequently, foundation assessment framework is detailed with the following steps: (a) collection of field bathymetry data; (b) collection of mudmat as-built data such as skirt penetration and mudmat tilt readings; (c) mapping of the approximate actual contact area between the foundation and the seabed; (d) recalculating the foundation capacity by incorporating measured data based on design codes and guidelines; (e) evaluating the approximate foundation distortion due to the undulating seabed surface using finite element method.