Do I need to change my mobile phone when traveling to Australia? What business do you need to do? Mobile phones can be used there.

Most telecommunications companies in Australia use ordinary GSM networks, which are exactly the same as those in China, so domestic mobile phones can be used when they are brought to Australia. There are also companies in Australia that use 3G networks, which is the WCDMA standard. If you think roaming is not expensive, you can use Unicom's mobile phone number, as long as all mobile phones supporting wcdma can be used, just apply for a card locally.