Originally Posted by
gudugan
I haven’t used this but I won’t recommend it because you will get firewalled. Use a non Chinese SIM that roams into China. T Mobile works or SIM from Hong Kong
You sure about that? They have roaming agreements with many providers through certain specific providers that act as the "home" network.
This would only be the case if Unicom is the "home" network. Even if it is, they also have a SIM for Asia called Asialink that almost certainly would not use Unicom as the "home" provider otherwise people traveling in Japan and South Korea would get firewalled.