Abstract Objectives/Scope Preloading for three-legged jackups, an act of testing the seabed every time a jackup is positioned on a new location, is done by adding an additional weight, referred to as ‘preload’, generally in the form of seawater ballast, either for all three legs simultaneously, or on a leg-by-leg basis. Operating staff often misunderstand when, and more importantly, how each method should be used in different circumstances. This paper addresses the long-standing requirement with respect to this critical activity. Methods, Procedures, Process The authors have compared both preloading methods to check the results of the eccentricity of the hull loads and the effect it would have in the event of a leg run. The authors also examined the result on the structural stresses on the structure. Finally, the authors explain how each procedure should be actually carried out with the objective of minimizing the structural stresses as well as the potential for damage in the event of sudden settlement. A typical rig hull is analysed and the results presented. Results, Observations, Conclusions Marine Operating Manuals of Rigs give reasonably reliable guidance on the proper procedures for one generic preloading option. But the other option is somewhat incompletely explained, leaving it to the operating staff to interpret the process and the employ safe steps to prevent hull and leg damage. In existing manuals, the risks discussed remain limited to those imposed by soil failure. Little comment is made on the stresses imposed on the hull members. Due to this lacuna, jackup rigs continue to expose their units to higher stresses by adopting less than optimal preloading methods. The result of this study by the authors is an effort to help explain, not just when each option needs to be exercised, but more importantly, how this needs to be done. It also records what happens to the hull structures when the operating staff choose one method over the other. This paper also brings out a stark omission in present day Marine Operating Manuals and provides a clear call to the industry on what needs to be added to this important document to ensure that operating personnel are not left guessing where it comes to choosing the preferred method for this critical task. Novel/Additive Information For over seventy-five years, it has been left to the operating staff to interpret the instructions on how exactly the preloading process must be performed vis-à-vis the different soil types. Surprisingly, neither the designer, nor marine warranty, nor rig owners have recognised this lacuna in the instructions to operating staff. This paper tries to close that gap by adding a methodology for choosing the preferred method that should be adopted.