Fluorinated organic molecules have found numerous applications in medicinal chemistry, as the incorporation of fluorine often improve metabolic stability, lipophilicity and bioactivity. Although the preparation of aryl and aliphatic fluorides have been extensively investigated, alkenyl fluoride synthesis remains to be under-developed due to challenges associated with stereoselectivity control. Herein, we report a practical method for stereospecific synthesis of terminal alkenyl fluorides, and especially their deuterated analogues using an Ag-catalyzed decarboxylative protonation/deuteration strategy. The synthetic utility is demonstrated by broad substrate scope, scale-up experiment and product derivatization. DFT computations recognize bimolecular NMP coordination to Ag as the favourable mode, elucidate the mechanistic pathway, and provide in-depth insights into the origin of reactivity difference, which fully support the experimental data.