Following the request for dual sim capability in the Iphone, Apple has responded favourably and introduced it but only in China for starters.

"Speaking of worldwide capabilities, one thing we've had requests for is dual sim capability. Some of you know what this is for, for the rest, here is the reasons people want dual sims, some people want two phone numbers on their phone, maybe a home number and a work number," Apple announced on Wednesday September 12, 2018.

"Some want two different plans depending on the region in the world they are in and what they need, and many of us like to travel and keep our local number but mainly to get a data plan in the region we are in, so we can have access to fast data there. To do this into Iphone XS and XS Max, we've built a technology called DSDS [Dual Sim Dual Standby].

There on Wednesday, Apple announced that the iPhone Xs, iPhone Xs Max, and iPhone Xr would all support dual SIM technology.

This will allow users to have two phone numbers with two different plans to run on the same phone. It’s also ideally suited for when you’re visiting a different country.

To provide dual SIM support, Apple is using the eSIM technology that’s already being used in Apple Watch.
This will act as a software-based SIM alongside a physical SIM card.

Both are enabled on the same smartphone at the same time and correspond to separate phone numbers, with two separate plans.

Thanks to Dual SIM Dual Standby technology, both SIMs remain functional at the same time. It activates the relevant SIM for an incoming call from one of the two numbers.

At launch, Apple’s working with various carriers to enable the eSIM, including AT&T, Verizon, T-Mobile, Vodafone, Bell, and others.

There’s also going to be a regional version for countries like China where eSIM technology isn’t readily available

Only in China

Dual SIM support -- which lets a phone use two phone numbers and carrier plans at the same time -- will be coming to the iPhone XS, XS Max and XR. While rumors suggested it would be limited to countries where multiple SIM use is more common, it appears the function will in fact be available worldwide -- as long as your carrier supports it. (Apple listed Verizon, T-Mobile and AT&T among several other telecom companies.)

But here’s the thing: While everyone else gets dual SIM capability via a single physical nano SIM combined with a digital eSIM, China gets something unique. Instead of an eSIM, the iPhone XR and XS Max in China will have a special SIM tray that holds two physical nano SIM cards. (There does not appear to be an iPhone XS that can hold two nano SIM cards.)

Part of the reason could be that eSIM isn’t prevalent enough yet in China.

Apple’s website for the Apple Watch 3, which uses eSIM, shows that China Telecom only supports cellular service for the device in 7 major cities including Shanghai (but notably not Beijing.)

Another major carrier, China Mobile, only introduced eSIM services in June -- starting in 7 cities that also don’t include Beijing.

All this means if Apple was to launch an eSIM iPhone in China, many users wouldn’t actually be able to use that capability yet -- rendering the dual SIM feature useless.

Yet most Android smartphones sold in China already ship with dual SIM. With the competition in mind, it’s understandable why Apple has made the extraordinary move to make a different set of iPhones just for Chinese customers.

As for those of you living outside China, Apple says the dual SIM function won’t work immediately. It’ll be enabled through an eSIM software update later this fall.

While it’s rare for Apple to create models specifically tailored to one country, it’s not unheard of. Different iPhones support different wireless bands depending on what carriers in each country use. And the iPhone 7 and 7 Plus in Japan supported Suica, the NFC cards used on trains in the country.