Moving to Tokyo and looking for International Schools

Hello, we are moving to Tokyo from Sydney and I would like to learn what international schooling is available for my 5, 7 and 9 year old children. We are looking at co-educational schools. It would be wonderful to get recommendations.
I am also looking for advice on whether we arrive in May (which is better for my husband who is going to be posted there asap) or I wait until the Summer holidays are over and arrive with the kids ready for the new school year in August.

I'm new to the expat world, so I can't give much advice but we also are considering a potential move (not sure on the timing yet). I've read a bit about the transition and the author of the book I am currently reading highly recommended avoiding an arrival at the beginning of summer break in terms of kids making friends more quickly, etc. So tough to know ahead of time which would be better!!