With the launch of its latest iPhone Xs, Xs Max and XR models, Apple has finally delivered dual SIM card capability to make overseas roaming easier for travellers. Well, sort of. Here's what you need to know about the new dual SIM iPhones and how to use them for global roaming.
Which new iPhones have a dual SIM feature?
All three models in the 2018 iPhone line-up – the Xs, the big-screen Xs Max and the more affordable XR – come with dual SIM technology.
However, only the Xs Max and the XR (not the standard Xs) iPhones sold in Hong Kong, Macau or China can accomodate two physical SIM cards – which Apple has achieved by letting two nanoSIM wafers sit back-to-back in the usual card slot.
Everywhere else in the world, Apple sells the new iPhone Xs, Xs Max and XR with one physical SIM card slot and a digital 'embedded SIM' (eSIM) module which taps into your carrier via an app, without the need for one of those tiny, fiddly and easy-to-lose wafers.
Apple already offers eSIM connectivity on recent Apple Watch releases, although the eSIM module of the new iPhones won't be available when those devices launch over the coming weeks – Apple says an update to iOS 12 due in November 2018 will activate the eSIM technology.
Setting up a dual SIM / eSIM iPhone
There are two ways you can use the SIM card + eSIM combo in a new iPhone Xs, Xs Max or XR.
1. use the physical SIM card slot for your home carrier, and rely on activating the eSIM with a local service when you roam
2. use the eSIM module for your home carrier, and insert a local prepaid SIM card into the iPhone when you roam
At the time of writing, barely a dozen carriers around the world will allow local iPhone subscribers to connect via eSIM – and for Australian readers, that list doesn't include Optus, Telstra or Vodafone.
This means that most globetrotting owners of a new iPhone Xs, Xs Max or XR will still need to stay connected by popping a nanoSIM into the card slot, and when it's time to travel, either
1. sign up for a roaming eSIM service, or
2. do the reliable old SIM card swap routine
The first option will work only if the country you're visiting has a carrier which supports the eSIM on traveller-friendly prepaid plans, or if you opt for a global provider such as GigSky or Truphone offering mobile services in dozens of countries.
Either way, the process will be the same: download an app for your chosen carrier, select your desired plan – which will be charged through your Apple App Store account – and you're on the air.
This should work a doddle if you log onto a free WiFi network on arrival at the airport or at your hotel. Likewise, topping up your account during your stay – and reactivating your plan if you return to that same country later on – will simply take a few taps of the screen instead of buying a recharge card.
However, until the eSIM is more widely supported around the world you may end up doing the familiar SIM card swap each time you travel, replacing your home carrier SIM with a card for a local prepaid carrier plan.
Using a dual SIM iPhone
Apple's November update to iOS 12 will add the ability to manage two numbers – one per SIM, and designated as Primary and Secondary services – through the Settings app.
When you're roaming you can select to use that number for making or receiving calls and messages, for mobile data as well as apps such as iMessage and FaceTime.
Both lines can remain active at the same time, so that when travelling you can still receive calls from home on your regular number.
You'll also be able to keep multiple plans associated with your eSIM, and activate each one as needed.
So, should I buy a true dual SIM iPhone from Hong Kong, China or Macau?
If you need two SIM card slots – not one physical slot and one eSIM digital module – you can certainly pick up an iPhone Xs Max or Xr on your next trip to Hong Kong, China or Macau. The device will still be covered by Apple's international warranty.
However, the iPhones sold in China don't work on the 700MHz frequencies used by Telstra and Optus for their high-speed 4G networks (respectively known as 4GX and 4G Plus), so you'll miss out on getting maximum download speeds in Australia.
Additionally, the AC power adaptor will be fitted with prongs to suit that country's AC socket type (Hong Kong and Macau use the same Type G socket as the UK, while iPhones sold in China comes with a US-style Type A plug) – so you may well need to rely on a plug adaptor to match the imported iPhone to your own country's socket type.