Depending on the method of incision.
Above the muscle incision (Through Nipple)
Tattooing the nipple colour can hide the scar. Although this method is not usually preferable for breast implant as this may damage milk glands, some patients find this method of incision less painful post-op.
Under the muscle incision (Through the breast fold, most preferred method by most patients)
This method is most preferred with a short incision point from the breast fold. The scar will be hidden. Patient can opt to laser and lighten the scar.
Through the armpit incision
This method is very blunt as the incision point is furthest away from the breast. Most plastic surgeons will only choose round implants for this procedure. The scar is well hidden through the armpit as well.