Phone compatibility?

If I purchase an unlocked Samsung Galaxy s3 in Europe and then take it with me to Japan, will I be able to stick an NTT Docomo (for example) SIM card in there without encountering any incompatibility issues?

To sum it all up, will it work in Japan?

Thank you.

Of course you won't know until you try.
As long as it's unlocked / SIM-free it SHOULD work especially because Docomo has the S3 in their series of devices.
The Japanese version of the smartphone is a bit different, though.

I heard a few people got it to work with Softbank, so it should also work with Docomo.
Just check the frequences of your model and the ones Docomo is using!

I used to work with customer care for a cell phone company. The best thing to do is ask your service provider. They are more likely to know exact solutions to what you need. If the phone/service works there or if not partners they can refer you to.