Chalk is a silt-sized soft biomicrite rock often encountered as a low to medium density, high porosity, structured material within a fractured mass. In recent years, there has been increased interest in the behaviour of chalk and the development of new design procedures for pile foundation installation design, motivated by several large-scale onshore and offshore infrastructure projects. Recent modelling has demonstrated the importance of accurately characterising the operational stiffness of the chalk mass. In contrast to sands and clays, the stiffness of the fractured chalk mass dominates the in situ mass stiffness. Stiffness measurements in the laboratory on samples, purposefully selected to be free of defects or fractures, tend to give higher results than those measured in situ, by factors that relate to the degree of fracturing.s While several methods exist to measure the chalk’s stiffness in situ, they are often subject to significant scatter, with no guidance available to the end user on interpretation or on which method should be used as a baseline. This paper describes a comprehensive programme of multi-method in situ geophysical testing in chalk at a well characterised test site in Southern England that forms part of a wider research project. The chalk deposit is relatively uniform with depth and provides a unique opportunity to apply multiple methods and interpretations without the influence of significant layering. The experimental programme is described and the interpretation and selected results of in situ tests at depths up to 40m are described. The chalk’s remarkably high shear stiffnesses are shown to be highly repeatable and consistent when rigorous test execution and analysis is applied. Recommendations are given for test set up, execution and interpretation of in situ tests in fractured chalk masses and the results provide benchmark data that can be used in future analyses.