A suggestion based on my experience of this trip:
the wifi on this ship was slow. We also bought Japan data-only SIM cards. They are cheap and speed is great. My nieces even used them to download movies on their iPhones and watched them in staterooms. when we were at port or on land, we switched from princess wifi to SIM cards. And every time when the ship left port, we still could enjoy high speed internet from the SIM cards for a couple more hours until the ship was too far from land.