Electrolytes have been used as thermodynamic ice inhibitors since they can depress the melting point of ice by lowering the activity of water. However, the kinetic aspects of electrolytes on ice nucleation have been unclear. Here we report an experimental study of the nucleation rate of ice in quasi-free droplets of eight dilute monovalent salt solutions suspended at an interface between two immiscible liquids of perfluoromethyldecalin and squalane. The studied salts were sodium chloride (NaCl), potassium chloride (KCl), lithium chloride (LiCl), sodium bromide (NaBr), potassium bromide (KBr), lithium bromide (LiBr), sodium iodide (NaI), and potassium iodide (KI). The results showed that some monovalent salts increased the nucleation rate of ice at low supercoolings (high temperatures), and this increase was largely independent of the salt concentrations up to 100 mM. This finding is in marked contrast to the previous finding that the same combinations of the monovalent salts promoted the nucleation of methane−propane mixed gas hydrates, suggesting that a fundamental difference may exist between the nucleation mechanisms of ice and clathrate hydrates.