That's how it used to be for me, then something happened.

I tried to upgrade my 3G plan to a 4G plan at a Unicom store in Xujiahui, Shanghai. I don't remember exactly when but it was right after the new plans were introduced.

I was told in the middle of the process (because I'd asked how roaming worked differently on the new plan as opposed to my current plan) that if I wanted to be able to use international roaming after upgrading, I'd have to put down that 500RMB deposit. I told them no, and they left my plan as is. I thought.

Then I called Unicom just before heading back to the States (I like to keep a Chinese number active for 2FA for online banking and Alipay), and was told that my account was a 准预付费 or some such and that deposit-free roaming was no longer available to me. Obviously I wasn't put back on the plan I'd started out with before the upgrade attempt.

Thankfully CMCC only requires 200RMB be in my account when it's activated to do it.

Yup, I had the same experience as jamar a couple months ago. Tried to activate international roaming on a new-ish SIM with ~300RMB of credit and was told I'd need to top up to a balance of at least 500RMB before they could activate international roaming. Added the credit via WeChat while I was on the phone with the rep and they activated roaming without further incident.

It really wasn't a big deal with the way I burn through Unicom credit anyway, but definitely a minor annoyance.

I got an SMS from China Mobile Beijing today announcing that in accordance with government direction they were starting real-name registration of existing numbers. It said your service might be affected if you don't register, but wasn't specific.

You can register through an app, but I didn't download it so I don't know whether passport holders can register online, or have to do it in person instead.

Which app is it? You need the passport to register, how does it work with an app?

Like I said in my post, I didn't feel like downloading it, so I don't know how or if passports are handled.

But you can download it yourself and see if you want. Apparently there's a link to 实名登记 on the home page of the app.

http://mobilebj.cn/?c=144/

I'll be in HK for 3 days and then China for about a month from the 24th. What's the cheapest way to get about ~10gb of mobile data? As far as I can tell, prepaid data on Unicom costs about 100rmb per GB?

Using this: http://www.3gsolutions.com.cn/3s3000s it'll cost me about $150USD assuming I use one SIM for a few days until the calendar month ends and switch over to the 6gb SIM in May.

1. Pay as you go in HK
2. Unicom for your month in China

My go-to in HK is 3. Grab their 2-day LTE SIM (I think you can top up more to use a third day) and you're set.

I'd second moondog's suggestion for China, but:

I'd also buy a Unicom or China Mobile (if your phone supports it) SIM while in HK to have on hand just in case. On the off-chance you need it, HK$68 for 500MB (Unicom HK) or HK$198 for 2GB (CMHK) isn't really that bad for reliable access to outside internet. Yes, VPNs work most of the time. My CMHK SIM has worked for me all of the time. I used the daily rate when I was in Shanghai for Spring Break- HK$48 daily for 1GB then unlimited but throttled to 128k after. Done and done.

That and with CMHK's $300 paid = $400 top-up, that's 4GB or 8 days of unlimited data for HK$300. Pricey, but not unreasonable. Unicom HK doesn't have a top-up bonus so they're not so great a value but if your phone doesn't support TD-LTE, they're another option if you want it.

@jamar:

Haven't used pre-paid sims before but have a question on the China Unicom HK Dual Number Cross Border King Extra card which is $HK68 for 500MB as you mentioned except looking at their packaging online, it says $HK0.80/MB next to it. Does this mean that if the 500MB is used up, it will start charging $HK0.80 per MB without you even knowing if you had any available credit on the sim? If not, how does one usually use another data pack without having to get charged $HK0.80 per MB first. Also, I noticed on the cugstore.com website, some cards are marketed as up to 42Mbps while some like the $HK68 for 500MB is listed as 3G, are they both the same data speed or is the 42Mbps ones faster? It seems they use 3's network in HK.

You'll get a text when your data balance is used up. I went through several GB of data in China last month this way. Due to delays in data usage reporting to the network, I may have overpaid (i.e. use data balance up without knowing it, use some additional data at overpriced per-MB rates, receive text an hour or so later, immediately recharge my balance and re-add new data package, rinse and repeat, etc.) as it always seemed like I was having to recharge more than I should have had to, but it worked to keep me connected to work with a minimum of Great Firewall hassles while I was traveling.

This is one reason why I prefer China Mobile HK. Their data has overpriced per-MB charges too, but the daily rate also functions as the maximum overage charge; you will never be charged more than HK$48 daily no matter how much you exceed your plan. The other thing is that when you run out of a monthly package, your data just gets shut off until you type in the USSD code to drop your package (going to the per-MB/daily rate) with the option to resubscribe to your package if you'd rather not pay by the MB/day.

Thanks @jackal. I was confused as I was looking at the tariff section here:
http://www.cugstore.com/usa/prepaid-...vice-plus.html

This seems to imply that you'll get charged HKD$0.80/MB after the 500MB is used up automatically. I plan to use the hotel's wifi with VPN as the multiple 500MB's can get expensive so will only use it for things I need on the mobile phone. I had the cards shipped from their mobile store but using the sim card number, have not been able to top up as the card starts with $HKD80 unactivated but once you activate, it's $HKD62 remaining so it's $HKD6 short for the data package. It seems like using the sim card number is only possible for data only cards as it comes up with a error saying it's unable to find the card so I wonder for topping up using the mobile phone itself, will topping up work when using MasterCard since it has to go through the securecode thing.
China Mobile HK's data package only supports China and HK. In my case, I also needed Macau but I discovered the Voyage King card is better for that purpose. You're right that China Unicom HK is more expensive as $HKD68 gets you 500MB while with China Mobile, atleast on the data only card, it's $HKD100 for 1.5GB's. Ofcourse it seems like the other advantage of the China Unicom card is incoming calls are free assuming someone actually calls you. Their topup provides a discount of 2% for anything $HKD50 and higher.

There are street vendors around Shamshuipo and probably other areas selling those cards at a discount.

cugstore.com sells the cards at a discount even though it's a small one. I won't have a chance to buy them in HK as the first part of my trip is on CX transiting at HKIA to a flight to PVG.

CX sells data-only CMHK SIMs in their inflight duty-free at a slight discount off face value. Not as good a discount as you'd get buying from Sham Shui Po but still something.

If you need something with voice then you'll have to go landside- there's a CMHK shop on the departures level.