Join Date: Aug 2009
Location: Houston, TX - Energy corridor
Bikes: 2011 Trek SOHO Deluxe, and 2010 Specialized Roubaix Expert
I can get maps for any part of the world as freeware and load them onto my Garmin Edge 800. The GPS satellites should be accessible in Japan. The US Government controls most GPS satellites. I see no reason why they would block signals in Japan. GPS units are quite prevalent in Japan. Japan does not use GSM for phones; so, most US phones won't work there.
I love my Edge 800.