MattAlt:Having made the trip from Tokyo to Palau, I can tell you that it isn't exactly a close destination. You'll spend an entire day getting there unless you can get nonstop tickets, which are only sold during certain seasons. Even then Okinawa is much, much closer.
Be aware that there are often differences in "diving cultures" between Japanese dive ops and those of other countries, so make sure you are really explicit about the style of diving and level of safety you expect. Good luck!
It's close compared to going from Sweden. From here to Palau it is 2.5-3 days travelling away. So an 'entire' day is nothing for me.
cheers
/christian