I'm planning a summer 2011 trip across Hokkaido, Japan. I'm currently mapping the route here and would like to get feedback and recommendations about GPS units. Have you used one in Japan? Will any GPS unit work in Japan, or are they like mobile phones and restricted by regional or national carriers/territories?

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.

I am pretty sure most Garmin GPS's will work just fine. They do sell worldwide maps via CD or microsd card for these units..

I would look at the Dakota 20 - small enough to use as a bike gps but larger in size vs bike specific gps's.. I own the larger version which is the Oregon series and while it works great, is a little big for a bike computer.. The biggest problem with many of the Japanese specific maps is that they will be in Kanji. You can get a worldwide map set but I doubt it will have the specifics you may desire.. There are many GPS websites to throw questions out to: https://gpsunderground.com

reviews:

https://www.gpsinformation.org/penrod/dakota/dakota.html
https://www.gpsfix.net/gamin-dakota-2...t-impressions/

Info about support for maps of Japan from Garmin.

You can check this site.
GPS Tracker

I bought one from there last month, and it works so cool.
Hope it would help.

If you are concerned about GPS reception in Japan, I don't think you need to worry at all. GPS signals are received by aircraft all over the world including Japan. It's not like cell phone frequencies varying in various countries. I have used a gps while in Taiwan that was purchased in the states with no problems.

Are there gps cases that protect the unit, while also being installed on bike mount at same time?
Or other alternatives to protecting gps in a crash or fall?

I like my Garmin 800