Excuse me, what business do you need to open with Unicom card for overseas travel?

International roaming function needs to be enabled. You can open the international roaming function through the mobile phone business hall or call the local customer service phone. If you don't need the internet access function in international roaming, it is recommended to turn off the internet access function of your mobile phone. If you don't turn it off, updating your mobile phone software or surfing the Internet with your mobile phone will generate high traffic charges. If you need to use your mobile phone to surf the Internet, it is recommended to contact local customer service to handle international roaming data packets, which is convenient and fast.