Enables the transfer of a solute or solutes from one side of a membrane to the other according to the reaction: glucose 6-phosphate(out) + phosphate(in) = glucose 6-phosphate(in) + phosphate(out).
MetaCyc:TRANS-RXN-33; RHEA:71535; Reactome:R-HSA-198513 "SLC7A4 exchanges G6P for Pi across the ER membrane"; Reactome:R-HSA-3229118 "Defective SLC37A4 does not exchange G6P and Pi across the ER membrane"; Reactome:R-HSA-3257122 "SLC37A1, SLC37A2 exchange G6P for Pi across the ER membrane"