The strongly oxidizing, powerful electrophilic fluorination reagent FXeOTf is shown to effect direct oxidative monofluorination of sulfoxides. This one‐step, chloride promoter‐free methodology provides access to so far inaccessible, yet highly desirable strongly Lewis acidic fluorosulfoxonium cations from electron‐deficient and/or sterically demanding sulfoxides that are shown to be practically unreactive towards the previously reported XeF2/NEt4Cl system. Experimental and density functional theory studies have been conducted to assess the Lewis acidities of the prepared sulfur(VI) cations. Preliminary results obtained with chiral sulfoxides provide early insights into the mechanism of these fluorination reactions. Highly Lewis acidic fluorosulfoxonium cations can be prepared in a one‐step, chloride promoter‐free fashion from electron‐deficient sulfoxides using FXeOTf. The latter is prepared by reaction of XeF2 with TMS‐OTf, thus representing an inversion of the previously described Umpolung strategy, which failed to convert the same sulfoxides efficiently. The Lewis acidities of the obtained cations have been probed experimentally and computationally.