The fact that Chinese domestic cell users can only use phones sold in China on eSim, and as soon as they leave China the eSims no longer work, gives me pause that there is some nascent security hole in them.

Why would they take such extreme measures if there wasn’t some issue with the security?

▲

uni_baconcat 11 hours ago | parent | next [-]

Incorrect. Chinese mobile carriers only issue eSIM to their approved models, which are devices sold in China. Once the eSIM is activated, users can roaming with their Chinese phone number to any country just like a physical SIM card.

Also, iPhone and iPad sold in China can install and activate an eSIM from foreign carriers when the device is not located in China. They only banned activating foreign eSIM within China.

▲

daft_pink 3 hours ago | parent | next [-]

Thanks, It seems I misunderstood the restrictions when they were first introduced. The purpose appears to be preserving the Great Firewall by preventing Chinese citizens from easily bypassing it with a foreign eSIM. Unlike a physical SIM, which must be imported and activated abroad, a foreign eSIM could be downloaded directly onto a domestic phone, making circumvention much simpler. By restricting eSIM activation, authorities effectively require someone to import a separate device, such as an iPhone purchased overseas, and keep it alongside their domestic phone if they want to activate and use a foreign eSIM within China. I had first read about these restrictions when the iPhone Air was announced but not yet released, and at the time the rules were not clearly explained, which led to my initial misunderstanding. Thanks so much!

▲

kube-system 11 hours ago | parent | prev [-]

> They only banned activating foreign eSIM within China.

Is that even a ban? I didn’t think eSIM activation typically roams — I thought it only worked on home networks.

	▲	Shank an hour ago \| parent \| next [-]
		> Is that even a ban? I didn’t think eSIM activation typically roams — I thought it only worked on home networks. While I was in the US, I swapped iPhones and successfully activated both NTT docomo and Au (KDDI) eSIMs while roaming. It definitely works when you're out of home network.
	▲	bux93 10 hours ago \| parent \| prev \| next [-]
		I activated a Thai SIM (True) inside of Europe before traveling no problem, so it's not a technical limitation. I think brands like Saily that specifically target travelers are also activated beforehand, so when you arrive you immediately have data.
	▲	wkat4242 10 hours ago \| parent \| prev \| next [-]
		True, both networks I have in Europe don't allow it. It's one of the reasons I don't like eSIM, there are a lot more restrictions than with real SIMs. With those I can simply pull one of my cards out of my phone and put it in my tablet or 4G modem for an hour while travelling. With eSIM I have to unregister it and get a new QR every time, registering it doesn't work abroad, and they can deny activation based on the device.
	▲	alibarber 10 hours ago \| parent \| prev [-]
		Mysterious - I have downloaded UK eSIMs over WiFi, and then activated/connected as if I were roaming, from other parts of Europe.

▲

numpad0 10 hours ago | parent | prev | next [-]

I did come across non-English article that all-eSIM policy is destroying grey market imports into primarily China and also into Russia. Previously one could easily flip iPhone at or above MSRP to milk carrier subsidies, but those flippers aren't taking iPhone 16/17 as it's harder for the clientele in totalitarian and/or sanctioned countries to use it.

I'm not sure if it's an undisclosed security hole or a backdoor, but there does seem like the eSIM push has something to do with China.

▲

okanat 11 hours ago | parent | prev | next [-]

It could be simply IMEI tracking. Turkey also has it. Without being registered in the country registry, the modem just stops getting answers from cell towers.

▲

notpushkin 11 hours ago | parent | prev [-]

To prevent them from using Hong Kong eSIMs to bypass site blocks?

	▲	thenthenthen 4 hours ago \| parent [-]
		It is interesting, my EU iPhone can use Chinese eSims unrestricted in Mainland (via trip.com), advertised as HK/Macao/Mainland travel eSims. As other have said, iPhones for the Chinese market can not. So the phone smuggling is still big business. Also, there is a quota on the amount of sims given out each month, but dont er quote me on that (at least that was the case with physical HK/Mainland sims sold in HK Shamshuipo etc).