How to use China Unicom number in South Korea?

Roaming charges for China Unicom users in South Korea:

Calls to roaming destinations are 0.96 yuan/minute, calls to mainland China (excluding Taiwan, Hong Kong and Macao) are 0.96 yuan/minute, calls to Taiwan, Hong Kong, Macao and other countries and 3.86 yuan/minute in the region, 0.96 yuan/minute in the roaming area, 0.36 yuan/minute in sending text messages to mainland China (excluding Taiwan, Hong Kong, and Macao), and 1.26 yuan/piece in sending text messages to Taiwan, Hong Kong, Macao, and other countries and regions.

Data tariffs are as follows:

1. Automatically upgrade preferential packages: 5 yuan will be charged for data traffic generated on that day (referring to Beijing time). 5MB of data traffic can be used. If the data traffic exceeds 5MB, it will automatically follow 5 Yuan/5MB charge, if it reaches or exceeds 5 times, it will be upgraded to a preferential package at 25 Yuan/day, with a cap of 25 Yuan. If the cumulative traffic on the day exceeds 200MB, the maximum Internet speed will be reduced to 384kbps. There is no need to order and no traffic will be generated on the same day, and there will be no charge.

2. Roaming data daily package (referring to Beijing time): You can activate the 20 yuan/300MB data daily package through SMS (send KTGM2 to 10010) (automatically superimposed without limit the number of times), and you can enjoy high-speed Internet access throughout the process. It will take effect immediately after successful activation, billed on a daily basis, and will be valid until May 31, 2020.