Using an iPhone 12 in Dual SIM mode throttles the cellular data speed to 4G LTE, according to an Apple Sales FAQ shared with retailers and carriers.
All 5G iPhone 12 models support Dual SIM mode, which refers to the ability to switch between a SIM card and an eSIM operating on independent numbers and/or carriers. However, an image of a training document from Apple's Sales Web resources called "What you need to know about 5G on iPhone" and posted to Reddit suggests the iPhone 12 will not support 5G on either line when Dual SIM mode is active. The FAQ reads:
"Does 5G work with Dual SIM?" When using two lines in Dual SIM mode, 5G data isn't supported on either line and will fall back to 4G LTE. If customers are using eSIM only and are on a 5G-supported carrier and service plan, they'll have 5G access.
The document suggests that only by disabling one SIM or the other will 5G speeds be available – a limitation that, if confirmed, will come as a blow to iPhone 12 customers who intended to use separate work and personal lines, for example.
On the bright side, this incompatibility could be a software issue, and therefore something Apple could resolve down the line. Indeed, the Reddit user who posted the above image claims that an update coming later in 2020 will enable 5G when using a Dual SIM mode.
This information is allegedly revealed in Apple's internal training documents, but 5G is not anywhere mentioned in Apple's Dual SIM support page, which was last updated on September 26. We've reached out to Apple to clarify the matter and will update this article if we get a response.
(Thanks, De Paul Sunny!)
Update: MacRumors has received independent confirmation that the documentation is genuine.
Thursday July 10, 2025 4:54 am PDT by Tim Hardwick
Apple will launch its new iPhone 17 series in two months, and the iPhone 17 Pro models are expected to get a new design for the rear casing and the camera area. But more significant changes to the lineup are not expected until next year, when the iPhone 18 models arrive.
If you're thinking of trading in your iPhone for this year's latest, consider the following features rumored to be coming...
A new Apple TV is expected to be released later this year, and a handful of new features and changes have been rumored for the device.
Below, we recap what to expect from the next Apple TV, according to rumors.
Rumors
Faster Wi-Fi Support
The next Apple TV will be equipped with Apple's own combined Wi-Fi and Bluetooth chip, according to Bloomberg's Mark Gurman. He said the chip supports ...
Apple's next-generation iPhone 17 Pro and iPhone 17 Pro Max are only two months away, and there are plenty of rumors about the devices.
Below, we recap key changes rumored for the iPhone 17 Pro models.
Latest Rumors
These rumors surfaced in June and July:A redesigned Dynamic Island: It has been rumored that all iPhone 17 models will have a redesigned Dynamic Island interface — it might ...
Thursday July 10, 2025 12:38 pm PDT by Juli Clover
Apple does not plan to refresh any Macs with updated M5 chips in 2025, according to Bloomberg's Mark Gurman. Updated MacBook Air and MacBook Pro models are now planned for the first half of 2026.
Gurman previously said that Apple would debut the M5 MacBook Pro models in late 2025, but his newest report suggests that Apple is "considering" pushing them back to 2026. Apple is now said to be...
iPhone 17 Pro and iPhone 17 Pro Max models with displays made by BOE will be sold exclusively in China, according to a new report.
Last week, it emerged that Chinese display manufacturer BOE was aggressively ramping up its OLED production capacity for future iPhone models as part of a plan to recapture a major role in Apple's supply chain.
Now, tech news aggregator Jukan Choi reports...
The long wait for an Apple Watch Ultra 3 is nearly over, and a handful of new features and changes have been rumored for the device.
Below, we recap what to expect from the Apple Watch Ultra 3:Satellite connectivity for sending and receiving text messages when Wi-Fi and cellular coverage is unavailable
5G support, up from LTE on the Apple Watch Ultra 2
Likely a wide-angle OLED display that ...
In select U.S. states, residents can add their driver's license or state ID to the Wallet app on the iPhone and Apple Watch, providing a convenient and contactless way to display proof of identity or age at select airports and businesses, and in select apps.
Unfortunately, this feature continues to roll out very slowly since it was announced in 2021, with only nine U.S. states, Puerto Rico,...
The iPhone 17 and iPhone 17 Air will be available in a total of nine color options, according to new information coming out of Asia.
The iPhone 17 Air's expected color options.
According to the leaker going by the account name "yeux1122" on the Korean blog Naver, accessory manufacturers are now producing camera protector rings for the iPhone 17 and iPhone 17 Air in colors to match their...
That's pretty unacceptable if true, and if its unfixable is likely to be a deal breaker for a small but important minority of power users (myself included).
If this is anything more than just an initial software bug (AKA if this is a hardware limitation) I really have to question whether or not the iPhone 12 is ready for prime time.
Ok... show me show Sidney is blanketed in 5G... today
I assume you mean Sydney. Here is one of the 3 networks for this little village. Covers where i live, work, run, drink, gym, BJJ and where 99% of my friends live. Next?
Order is now cancelled, sticking with XS for another year. Disappointing because I was looking forward to some new tech, but since I don’t take many pictures, the iPhone 12 already felt like only a smalll update.
i would not be able to use 5G at all, because I use dual sim 24/7.
I am waiting for the next iPhone with hopefully real 5G (including international UW) support, 120hz and a smaller notch. That will feel much better
Biggest design overhaul since iOS 7 with Liquid Glass, plus new Apple Intelligence features and improvements to Messages, Phone, Safari, Shortcuts, and more. Developer beta available now ahead of public beta in July.