As for the SIM card, you could use your carrier's international-roaming plan, but such plans tend to be very expensive. In addition, I wasn't sure about the coverage of my carrier's roaming plans in China. Using a SIM card that was "native" to China ensured that I would have coverage in the country. Local SIM cards also tend to be inexpensive, and they're easy to set up. (On the other hand, most of these SIM cards allow only local phone calls.)
I also got a battery case for my iPhone 3GS—since it is more than four years old and has been sitting in storage, the phone's internal battery no longer offered much usage time. The battery case allowed me to use the iPhone 3GS more than 7 hours before it needed recharging.
Pick a VPN
A VPN takes the Internet data you're transmitting and receiving and sends ("tunnels" in networking lingo) it through a private, encrypted channel so that no other servers—such as the Chinese firewall—can read it in transit.
You'll find dozens of VPN services online and in the iTunes store, but the Chinese government is constantly working to thwart the efforts of these VPNs. How do you find out which VPNs work in China? By using the Internet, of course—but you have to do your research before you get to China. BestVPN, a site dedicated to reviewing VPNs, had the most up-to-date information on VPNs for China that I found, so I used BestVPN's recommendations as a starting point.
I signed up for two VPN services, ExpressVPN and AirVPN, just in case one didn't work when I got to China. I also picked these two services both because they allegedly worked in China and because each offered short-term service plans. (Most VPN services I surveyed offer monthly or annual plans, which was more than I wanted.) At the time of my trip, ExpressVPN offered a seven-day free trial, which was perfect for me; I bought a €1 three-day plan for AirVPN.
I also sent email messages to the VPN services to ask about their availability in China. A representative from AirVPN sent me a very helpful reply, saying that the company's service worked on "business lines" but not on "residential lines." AirVPN also gave me some tips to try in case I experienced a service disruption. An ExpressVPN rep confirmed that its service worked in Beijing.
(During my trip, a friend told me that I could set up a free personal proxy server using Google App Engine. I didn't have a chance to try this approach, but if you have the time, you can give it a go by using Digital Inspiration's instructions.)
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