Wechat is international.

Use wechat if you can surf the internet. Many Chinese working in Singapore use WeChat. However, in foreign countries, it is really not recommended to continue to use GSM international roaming, the traffic is very expensive, and its settlement is not timely, which is easy to exceed the traffic.

You can buy a card locally in Singapore. There are more cost-effective packages, depending on the length of time in Singapore.

It's also cheap to call back to China.