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.
Earlier this year, YouTuber Jon Prosser shared multiple videos showing off what he claimed to be re-created renderings of what was then presumed to be called iOS 19 and which was eventually unveiled by Apple as iOS 26 at WWDC in June.
In his first video back in January, Prosser showed off a Camera app redesign with a simpler set of buttons for moving between photo and video modes, and he...
Wednesday July 16, 2025 6:50 am PDT by Joe Rossignol
We may finally have a definitive list of all color options for the iPhone 17 series, ahead of the devices launching in September.
MacRumors concept
In a report for Macworld today, Filipe Espósito said he obtained an "internal document" that allegedly reveals all of the color options for the upcoming iPhone 17, iPhone 17 Air, iPhone 17 Pro, and iPhone 17 Pro Max models.
The report includes ...
Apple previously announced that a public beta of iOS 26 would be available in July, and now a more specific timeframe has surfaced.
Bloomberg's Mark Gurman today said that Apple's public betas should be released on or around Wednesday, July 23. In other words, expect the public betas of iOS 26, iPadOS 26, macOS 26, and more to be available at some point next week.
Apple will be releasing...
Wednesday July 16, 2025 4:17 pm PDT by Juli Clover
We have just under two months to go until the debut of Apple's iPhone 17 models, and rumors have been ramping up in recent weeks. We went through everything we know so far, pulling out the most exciting rumors and highlighting some other changes that aren't going to be so great.
Top Tier
Ultra Thin iPhone 17 Air - The iPhone 17 Air is 2025's most exciting iPhone rumor, because it's the...
Wednesday July 16, 2025 11:31 am PDT by Joe Rossignol
Apple's long-rumored foldable iPhone will likely have a starting price between $1,800 and $2,000 in the U.S., analysts at investment banking firm UBS said this week. If so, the foldable iPhone would cost more than a MacBook Pro, which starts at $1,599.
With a starting price of at least $1,800, the foldable iPhone would be the most expensive iPhone model ever released, topping the Pro Max at...
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 ...
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 ...
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.
