<p>Under-reamed pile foundations have been a potential solution for enhancing axial capacity in challenging soil conditions like soft saturated marine clays. In this study, the performance of multi-tiny bulb under-reamed piles, a relatively new foundation technique, for its use in marine clay conditions is studied and compared with the conventional single under-reamed piles and uniform cross-section piles. Laboratory model pile tests were carried out at different interface shear strength and soil moisture conditions. Subsequently, finite element analysis was carried out using Plaxis 3D Ultimate software to augment the results. The test results indicated that the multi-tiny bulb under-reamed piles performed better than single under-reamed piles and uniform cross-section piles at different interface strength conditions and moisture contents considered. At conditions similar to field conditions, these piles outperformed uniform cross-section piles by 79% and 107% in compression and uplift, respectively. Furthermore, the capacities of these piles increased with the increase in their bulb diameter as well as bulb spacing. The studies revealed that the multi-tiny bulb under-reamed piles exhibited superior performance compared to other piles at all the testing conditions considered, under both compression and uplift loading. These piles could be used as an effective foundation alternative with less material usage compared to single under-reamed piles.</p>