<p>Preloading is a widely adopted technique for reducing secondary compression—axial creep under oedometric conditions—in soft ground, and it is commonly implemented in conjunction with the installation of vertical drains. The installation of vertical drains alters the drainage paths and may introduce additional uncertainty in long-term settlement prediction. However, the influence of drainage direction on creep behavior has not been sufficiently quantified in the literature. This study quantitatively evaluates the effect of drainage direction on creep behavior during different loading phases associated with preloading in soft ground. A series of oedometer tests was conducted under vertical and radial drainage conditions using reconstituted kaolinite samples and undisturbed samples obtained from the Nakdong River intertidal zone in South Korea. Under surcharge loading, secondary compression was greater under radial drainage. After unloading, although swelling under radial drainage was generally larger, creep reappeared earlier and developed to a greater extent. During reloading, secondary compression was again greater under radial drainage. Taken together, these results show that radial drainage consistently leads to larger long-term settlements across different stress stages. The findings of this study suggest that the installation of vertical drains could influence creep behavior under certain preloading-induced stress conditions, thereby increasing uncertainty in long-term settlement control of soft ground.</p>