The easiest way, and actually still relatively inexpensive way to go about this is to use a local SIM card with data roaming activated. I say it is relatively inexpensive because it cost only $8 for 1GB of data over a week if you use a Starhub prepaid card, and I think it is wise to do so. Forget about buying any other types of prepaid SIM card, or worse, renting a WiFi sharing device. M1 data passport is also very expensive ($25) in comparison.
Free access WiFi is widely available throughout China (malls, restaurants, hotels etc.), and when connected, you can access services other than Google, WhatsApp and Facebook (e.g. Yahoo mail). In fact, you will be able to receive WhatsApp and Hangouts messages every now and then through a WiFi connection, but you cannot send out messages.
There is a way to overcome this limitation and it’s called VPN (Virtual Private Network), whereby you need to first connect to a VPN server in another country (this is called tunneling). Once the connection is established, it will be as if you are using your device in that particular country.
I tried TunnelBear VPN and it worked well. It comes with a free data usage quota, and you can earn additional free data by tweeting about them. That’s 1.5GB which is probably enough data to last you through a 10 days travel period.
To be able to use TunnelBear, you need to be connected to a fast internet connection. Remember that having a strong WiFi signal does not mean having a fast internet connection. When the connection is poor, you may not even be able to connect to the VPN server. Here’s a tip: the server in Germany worked especially well. Forget about the servers in Hong Kong, Singapore and Japan. Another tip: you may need to turn on the GhostBear option before your arrival in China. I can’t verify if this is true because I did so and TunnelBear worked fine. Better to just follow suit.
Most of the time, I was able to use VPN while connected to the hotel WiFi network, so you will be able to save a lot of your 4G data roaming quota by using VPN. You do need a bit of patience when using VPN since the data has to be routed possibly from Singapore (or wherever the data center is) to Germany then to China, plus there’s time spent on encoding and decoding the data. Nevertheless, I’m sure you will not have any complaint when you’re getting access to your favorite social media platform for free.