A copper-free Sandmeyer-type fluorosulfonylation reaction is reported. Utilizing Na2S2O5 and Selectfluor as the sulfur dioxide and fluorine sources, respectively, aryldiazonium salts were transformed into sulfonyl fluorides. The one-pot direct synthesis of sulfonyl fluorides from aromatic amines was also realized via in situ diazotization. The practicality of this method was demonstrated by the broad functional group tolerance, gram-scale synthesis, and late-stage fluorosulfonylation of natural products and pharmaceuticals.