The most natural and common word to fill in the blank is when:
"I have a bath when I get home."
This indicates that you take a bath immediately after or at the time you arrive home.
اذا كان لديك إجابة افضل او هناك خطأ في الإجابة علي سؤال I have a bath ___ I get home اترك تعليق فورآ.