Changes of the topography of the Antarctic Ice Sheet (AIS) can complicate the interpretation of ice core water stable isotope measurements in terms of temperature. Here, we use a set of idealized AIS elevation change scenarios to investigate this for the warm Last Interglacial (LIG). We show that LIG δ18O against elevation relationships is not uniform across Antarctica and that the LIG response to elevation is lower than the preindustrial response. The effect of LIG elevation‐induced sea ice changes on δ18O is small, allowing us to isolate the effect of elevation change alone. Our results help to define the effect of AIS changes on the LIG δ18O signals and should be invaluable to those seeking to use AIS ice core measurements for these purposes. Especially, our simulations strengthen the conclusion that ice core measurements from the Talos Dome core exclude the loss of the Wilkes Basin at around 128 kyr.