Quick Answer
iOS 27's new iPhone Handoff feature is designed to let you switch the same phone number between two iPhones without repeatedly transferring your main eSIM.
One iPhone acts as the main iPhone, while the second becomes a companion iPhone with a companion eSIM.
Only one iPhone is active for cellular service at a time. The other remains passive until you switch devices.
The feature requires iOS 27 and carrier support, and availability may vary by carrier.
What Is iPhone Handoff in iOS 27?
iPhone Handoff is a new iOS 27 feature designed for people who regularly switch between two iPhones but want to keep using the same phone number.
Instead of manually transferring an eSIM every time you change phones, Apple is building a system around a main iPhone and a companion iPhone.
The main iPhone keeps your primary eSIM. The second iPhone receives a companion eSIM linked to the same phone number.
Apple's developer framework describes the underlying system as iPhone Quick Switch, with one enrolled iPhone being active and the other passive.
That distinction is important.
iPhone Handoff does not simply copy the same SIM connection onto two simultaneously active phones. It lets two enrolled iPhones take turns being the active device for the same number.
Credit by MacRumors
How Does iPhone Handoff Work?
When iPhone Handoff is configured, one device is selected as the main iPhone.
Your existing eSIM remains on that phone, while the second device is enrolled as the companion iPhone.
The companion device receives a separate companion eSIM associated with the same phone number.
Apple's current Quick Switch framework defines two states:
Active: Cellular service is available on that iPhone.
Passive: Cellular service for that number is currently held by another enrolled iPhone.
When you switch devices, the newly selected iPhone becomes active and the other becomes passive.
This makes iPhone Handoff closer to a phone-number handoff system than a traditional MultiSIM setup.
How to Use One Phone Number on Two iPhones
The current iOS 27 setup interface shows iPhone Handoff under Settings > Cellular.
During setup, users can choose which device will remain the main iPhone and which will become the companion iPhone.
The primary eSIM stays on the main device, while the second iPhone receives a companion eSIM linked to the same phone number.
However, the full activation process has not yet been broadly opened by carriers.
That means the exact setup flow may vary once supported carriers officially enable iPhone Handoff.
For now, the key requirements are expected to be:
-
Two compatible iPhones running iOS 27
-
A supported carrier
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A main eSIM on the primary iPhone
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Carrier activation of the companion eSIM
Can Two iPhones Use the Same Phone Number at the Same Time?
No, not as two fully active cellular devices.
Based on Apple's current iPhone Quick Switch framework, only one enrolled iPhone is active for the phone number at a time.
The active iPhone has cellular service, while the other remains passive.
When you switch devices, the cellular service moves to the newly active iPhone.
This is different from some carrier MultiSIM services where several devices can remain connected at the same time and may all receive calls.
So the simplest way to understand iPhone Handoff is:
Two iPhones can be enrolled for the same phone number, but only one is the active cellular device at a time.
Do You Need a Second Phone Plan?
You should not need a completely separate phone number just to use the companion iPhone.
However, the second device still requires a companion eSIM provisioned by your carrier.
That creates a separate question: will carriers charge for it?
Carrier policies may differ.
Some operators could include companion-device access with existing plans, while others may charge an additional monthly fee or require a specific plan.
Apple does not currently provide a universal pricing model for iPhone Handoff.
Why Would You Use iPhone Handoff?
The feature makes the most sense when two iPhones serve different purposes.
iPhone Ultra + iPhone 18 Pro
A foldable iPhone Ultra could be useful when you want a larger display, while a traditional iPhone 18 Pro may be easier to carry in other situations.
iPhone Handoff could let you move between them without maintaining two separate phone numbers.
Use an Old iPhone as a Backup
An older iPhone could become useful again as a secondary device for travel, outdoor activities or situations where you do not want to carry your main phone.
Use an iPhone mini as a Lightweight Second Phone
Someone using a large Pro Max or foldable iPhone could keep an older iPhone 13 mini as a smaller secondary device.
The same phone number could follow whichever iPhone is currently active.
Which Carriers Support iPhone Handoff?
Carrier support is likely to be one of the biggest limitations at launch.
| Carrier | Current Status |
|---|---|
| T-Mobile US | Support appears in iOS 27 carrier configuration, but is not broadly enabled |
| Deutsche Telekom | Early support appears to be in preparation |
| AT&T | No public support announced |
| Verizon | No public support announced |
| Japanese carriers | No public support announced |
T-Mobile US and Deutsche Telekom appear to be among the carriers preparing for the feature, but that should not be treated as broad public availability yet.
Updating to iOS 27 alone will not necessarily make iPhone Handoff available.
Your carrier must also support the companion eSIM and Quick Switch system.
iPhone Handoff vs Dual SIM
iPhone Handoff and Dual SIM solve different problems.
Dual SIM:
One iPhone uses two phone numbers.
iPhone Handoff:
Two iPhones take turns using the same phone number.
Dual SIM is useful when you want separate personal, work or travel lines on one device.
iPhone Handoff is designed for people who want to switch between different iPhones while keeping their main number.
Bottom Line
iPhone Handoff could make owning two different iPhones much more practical.
Instead of manually transferring an eSIM every time you change devices, iOS 27 is designed to let a main iPhone and companion iPhone share access to the same phone number through Quick Switch.
The important limitation is that this is not two simultaneously active cellular connections.
One iPhone is active while the other remains passive.
The biggest questions now are carrier availability, additional fees and how quickly carriers roll out support.
FAQ
Can two iPhones have the same phone number?
Yes. iOS 27 iPhone Handoff is designed to let a main iPhone and companion iPhone be enrolled for the same phone number.
Can both iPhones use cellular service at the same time?
No. Apple's current Quick Switch framework uses an active and passive device model. Only the active iPhone has cellular service for that number.
Does the second iPhone need another eSIM?
Yes. The main eSIM stays on the primary iPhone, while the second device receives a companion eSIM linked to the same number.
Is iPhone Handoff free?
That depends on the carrier. Apple has not announced a universal pricing policy for companion iPhones.
Is iPhone Handoff the same as Dual SIM?
No. Dual SIM lets one iPhone use multiple phone numbers. iPhone Handoff lets two iPhones switch access to the same phone number.
