Most of the baths are a decent size in the birthing suites - not a standard bath size but if you want a water birth try the Royal Womens - they are opening their new hospital on the 22nd and it sounds great - (lots of single rooms!) and I think they do water birth? From memory the Monash in Clayton and Angliss in Ferntree Gully ( a bit far sorry) do as well. Good luck getting the birth you want!