PS:
I am a Hongkonger which often goes to Mainland China and I am living with two friends which are Chinese and Hongkongers who often live in Mainland China First of all, plan on no access to Google services, not just Google search but also Gmail, and other service, even for Google Play store.
Other western social media like Facebook and Twitter are not accessible.
Microsoft seems to be in the good graces of the authorities.
There is no problem to access Microsoft services like Hotmail, Bing and Skype.
Most IM software are accessible in China, including Whatsapp and Skype.
In China the most popular IM software are Wechat and QQ, the first one is like Whatsapp and the second one is similar to ICQ.
However, Line is not accessible in China.
Actually the "height" of GFW depends on the "sensitive" day(敏感日), more website will be blocked when closer to these days, like 4th June which is the day of Tiananmen massacre.
You would expect more "western" website like Wikipedia will be blocked on those days.
Finally, VPN is not 100% blocked.
Many Chinese local use VPNgate to access prohibited websites.
VPNgate is free but the connection is not good.
On the other hand, you may purchase VPN services, which costs around 10 USD per month, depending on the speed and the amount of data.
Finally, there are some recent blog entries which may help you: http://onemileatatime.boardingarea.com/2015/05/11/internet-in-china-staying-connected-while-traveling/ http://rapidtravelchai.boardingarea.com/2015/04/05/an-update-on-internet-in-china/ http://travellingtheworld.boardingarea.com/2015/05/bypassing-website-location-restrictions/
travel.stackexchange.com/users/29988/Him
I'm a Chinese student who just came back to China from US a month ago.
As most VPN protocols have their own characteristics, GFW is able to detect VPN connections and reset/block VPN connections.
Although VPNs can be blocked, if you use your own server and don't have a very heavy traffic, you might still be able to use it.
One of the most popular methods in China now is Shadowsocks , a SOCKS5 proxy developed by clowwindy.
It's harder for GFW to detect as it obscures the pattern in packets.
Shadowsocks is very easy to deploy on your own server and there are also many people selling shadowsocks service online.
There is also a project called GFWList .
It records blocked websites and is used to achieve autoproxy switch.
A pac file generated from GFWList with hostnames can be find here: https://raw.githubusercontent.com/clowwindy/gfwlist2pac/master/test/proxy.pac
travel.stackexchange.com/users/23171/mrseaman
I haven't been to China, but I have visited Iran and the filtering technology is similar.
For the entirety of my world trip, before arriving in Iran, I was using a personal VPN from AnonyProz to secure my connection when eg using public Wi-Fi.
I was surprised to find that this VPN did not work at all in Iran, despite being run over port 443 (HTTPS/SSL).
This means that they deploy Deep Packet Inspection to detect the protocol being used rather than just blocking per-port (443 is needed for much of the web so is not blocked overall).
The one thing that does seem to work wherever you are is Tor .
I highly recommend you make sure you have a copy before you go, and then use it to bootstrap whatever other VPN solution you can find that works.
travel.stackexchange.com/users/4272/imoatama
Note: The following was true when I was in China in July 2013.
The information has probably changed since then, as the Chinese government continually revises their internet access policies.
In general, the big social networks (Facebook, Twitter, etc) are blocked from within China.
This applies to mobile devices too.
(I'm not sure about Whatsapp, I didn't try it when I was there last year, and it might have changed since then anyway.)
Gmail worked, and most other web-based email provides probably will too.
Most foreigners who spend a lot of time in China set themselves up with a VPN of some kind, which essentially tunnels their web traffic to somewhere outside of China before it hits the Internet.
If you Google for "VPN china" you will find a wide variety of choices.
The Chinese government seems to allow these VPN connections (and not try to block them), probably because most Chinese citizens wouldn't have a way to pay for them in any case.
The big credit card system in China is "UnionPay" which is accepted almost nowhere outside China.
Foreigners would be able to pay for VPN service somehow and the Chinese government isn't terribly interested in blocking foreigners' access to the Internet.
Finally, if you've got an unlocked cell phone then it's pretty easy to get a local SIM card with data service.
For example, for 100 RMB (about 12 €), you can get a prepay SIM card and with some amount (maybe 100 MB) of data.
Then you can top it up by buying additional credit.
The providers have systems that interact in both Mandarin and English.
(I think I had a SIM from China Unicom.)
travel.stackexchange.com/users/2363/Greg Hewgill
My experience is that social media and major news sites are normally blocked.
Likewise, Wikipedia.
You can usually get the news from a newspaper's website that isn't one of the big newspapers, although the filter will sometimes decide a certain page isn't to be had even then.
Note that I have also encountered an internet cafe that was running something that rendered Google useless and redirected you to Baidu--which would do a very poor job when given English search terms.
Edit: Since I wrote the above things have gotten worse.
The last time I was there nothing Google worked at all.
No Google, no Gmail, no Recaptcha
, I feel like there was something else that was gone
but I don't recall.
travel.stackexchange.com/users/1764/Loren Pechtel
Here is a list of blocked Alexa Top 100 domains: https://en.greatfire.org/search/alexa-top-1000-domains
You can also test your URL using there tools.
The IM you can use:
Skype iMessage
wechat
travel.stackexchange.com/users/19064/wuyefeibao
A friend of mine is going to China for almost a month until mid August.He want to know what kind of outside communication he will be able to use to communicate with his family/friends.   We already know that Facebook is blocked but is it also on mobile devices?Also what about Whatsapp that belongs to Facebook now?  Please if you have any resource online that you can link here that will be great. My Friend is from Central Europe.
Going to China - The Great Firewall
travel.stackexchange.com
<china><internet>
travel.stackexchange.com/questions/34347
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Expect western social media like Facebook and Twitter to be blocked, as well as much or all of Google services and major news sites, but email and many IM software is available. VPN is not 100% blocked, and many Chinese people use VPNGate or Shadowsocks, a SOCKS5 proxy developed by clowwindy. Finally, if you've got an unlocked cell phone then it's pretty easy to get a local SIM card with data service. Communications in China can be complicated. Google appears to be completely blocked now whereas Microsoft services are accessible. Most IM services work. Many people use VPNs, which are not all blocked. A local sim is an option if you have an unlocked cellphone.
Most social media and news sites are blocked in China. Google also now appears to be blocked. Microsoft services, like Hotmail, Bing and Skype, work, as do most IM services. VPN is used by many people and the Chinese government does not block foreign VPN services. With an unlocked cellphone, you can use a local sim card.