Somewhat of a dumb question. But is there a country where a PLB won’t work (ie, they don’t have a SAR team attuned to the signal it is sending). If I buy US version and register it, I assume it will still work when I go snowboarding in Japan, right?
It might work in Japan, but it would be illegal to use it:
"In Japan, basic GPS Satellite Messengers such as SPOT and Garmin inReach can be used anywhere by anyone as a quasi-PLB. More powerful radio-wave emitting PLBs, however, are a) restricted to use on the ocean and b) require a basic Japan wireless radio station license (無線局免許). Currently, only one make and model of 406MHz PLB is authorized for use in Japan - the Japanese version of the ACR ResQLink+ (on the ocean only, and only for license holders)."
Can I use a PLB in Japan? | The Hokkaido Wilds
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What happens if I use my PLB in Japan?
If a PLB is used in Japan by a non-licensed individual and/or on land, or a foreign-licensed user uses their non-Japan compliant device in Japan, this will be a violation of the Japan Radio Law (電波法違反), which carries a maximum penalty of 1 year imprisonment or a 1,000,000yen (US$9,200) fine. If the use results in interference with public communications (such as radio, TV etc), then the maximum penalty is either 5 years imprisonment or a 5,000,000yen (US$46,000) fine.
But really? Would a judge really impose such a penalty on someone simply seeking emergency assistance? To find out, I called the Hokkaido Bureau of Telecommuications (北海道総合通信局), the governmental agency overseeing the laws and regulations regarding the use of radios and other communications in Hokkaido. Their answer was understandably opaque. “We can’t say, as it would depend on the circumstances, and it would be up to the courts to decide,” was their answer."