The next stock is going to ship from early May according to BHphoto and FocusCamera. If you preorder the camera now you might get it in two weeks.
Sony A7III in USA at Adorama, BHphoto, Amazon, BestBuy, FocusCamera, BuyDig.
Sony a7III in Europe at Amazon DE, Calumet Germany, Amazon UK, ParkCameras UK, WexUK, Amazon FR, Amazon IT, Amazon ES.