Enables the transfer of a solute or solutes from one side of a membrane to the other according to the reaction: Na+(out) + Cl-(out) = Na+(in) + Cl-(in).
Reactome:R-HSA-5623705 "Defective SLC12A3 does not cotransport Cl-, Na+ from extracellular region to cytosol"
;
reactome:R-HSA-426130 "SLC12A3 cotransports Cl-, Na+ from extracellular region to cytosol"