I've been to korea and japan using a nokia e61. Used my att sim card and had no problem making or receiving calls or using data..of course when I got the $2500 phone bill the next month I almost had a heart attach, thankfully it was work realated and my employer paid the bill., I think the biggest part of that bill was data..verrrry expensive..If you are using a local SIM, if someone calls your US number you won't get the call as the local sim has it's own number. In any case, any phone with wcdma 2100 will work in both places...have a ball
I'm considering buying an unlocked GSM phone here in NY, because I travel overseas a lot. Therefore I need a quad-band GSM phone (probably sign up with AT&T for my US usage), but because I will travel to Korea and Japan also, I need a 3G or 3.5G phone that I can just use a local SIM card with. Is it safe to assume that any GSM phone with UMTS or HSDPA will work in Korea and Japan?
My interest in 3G is not because of the data speeds, it's only because I need to use a darn phone in Korea/Japan.
I am currently looking at the LG CU515, Samsung A707/Sync, and Nokia N75. Anyone had any experience with these in Korea or Japan?
Also, related to these questions, what happens when someone calls your US number when you are overseas with a local SIM card?