<p>Retrofitting existing shallow foundations to enhance stability remains a critical challenge in geotechnical practice, particularly when structural connection to the footing is not feasible. In such cases, peripheral skirts can be introduced to confine the soil beneath the foundation, forming an unconnected skirted footing system. This study numerically evaluates the undrained bearing capacity of strip and circular footings with unconnected rigid skirts using finite element limit analysis considering the soil subjected to undrained loading. The study account for the variation in the skirt embedment ratio (<i>L/B</i> or <i>L/D</i>, i.e., depth of skirt) and spacing ratio (<i>d/B</i> or <i>d/D</i> i.e., spacing between footing edge and skirt). Results indicate that unconnected skirts substantially increase the undrained bearing capacity factor (<i>N</i>_<i>cu</i>) when positioned close to the footing, with improvement ratios up to 1.39 for strip and 1.91 for circular footings. Beyond <i>d/B</i> or <i>d/D</i> ≈ 1, the skirts exhibit negligible effect, reflecting a critical threshold for the design. The failure mechanism in the soil is also examined where the unconnected skirts for strip footings prone to rotation compared to the more stable axisymmetric response of circular skirts.</p>