Dual SIM Setup on iPhone: Complete Configuration Guide

This guide covers the complete iPhone dual SIM configuration process — from adding a second line through every setting you need to configure before using both lines reliably. What Is Dual SIM? explains the underlying technology (DSDS, DSDV, DSDA). Using Dual SIM for Travel covers the operational details of using a travel eSIM abroad. This guide focuses on the setup itself.

Supported iPhone Models

The dual SIM capability on iPhone depends on the model and how the second line is added.

Physical SIM + eSIM

Any iPhone from iPhone XS (2018) onward supports one physical SIM card plus one eSIM active simultaneously. On these models, inserting a nano-SIM into the tray and adding an eSIM profile creates a two-line configuration.

Dual eSIM (Two eSIMs, No Physical SIM Required)

Starting with iPhone 13 (2021) and iPhone SE 3rd generation, two eSIM profiles can be active simultaneously without any physical SIM card. This is the only configuration available on eSIM-only models.

eSIM-Only Models

Some models have no physical SIM slot at all. Adding a second line on these devices means installing a second eSIM profile.

Source: Apple Support — Learn which type SIM your iPhone or iPad uses

Check your model: Open Settings > Cellular. If you see an Add eSIM option, your iPhone supports adding a second eSIM. If you see a physical SIM listed alongside an eSIM slot, your model supports the physical + eSIM configuration.

Before You Start

Before adding a second line, confirm the following.

Your iPhone is carrier-unlocked. A carrier-locked iPhone restricts eSIM activation to the locking carrier. Go to Settings > General > About and look for Carrier Lock. If it reads “No SIM restrictions,” your iPhone is unlocked. If it shows a carrier name, contact that carrier to request an unlock before proceeding.

You have a stable Wi-Fi connection. Downloading an eSIM profile requires an active internet connection. Connect to Wi-Fi before starting. If you already have one active SIM with data, that connection works too.

You have your QR code or activation code ready. Your carrier or eSIM provider sends a QR code by email or displays it in their app. Keep it accessible on a separate device — you cannot scan a QR code from the same iPhone you are configuring. On iOS 17.4 or later, you can long-press a QR code image in Mail or Photos to trigger the installation without a second device.

For the full QR code installation walkthrough, see How to Set Up eSIM on iPhone via QR Code.

Adding a Second Line (eSIM)

If you are new to eSIM technology, see What Is an eSIM? for the underlying concepts before continuing.

Step 1 — Open Cellular Settings

Go to Settings > Cellular.

If you have one line active, you will see it listed along with an Add eSIM button (or Add Cellular Plan on some iOS versions).

Step 2 — Tap “Add eSIM”

Tap Add eSIM. iOS presents three options:

• Use QR Code — scan a QR code provided by your carrier
• Enter Details Manually — type the SM-DP+ server address and activation code
• Use Carrier’s App — open the carrier’s app to complete activation automatically

Select the method your carrier or provider supports.

Step 3 — Scan or Enter the Activation Code

QR code method: Point your iPhone camera at the QR code on a second screen. When recognized, tap Cellular Plan Detected, then tap Continue and Add Cellular Plan.

Manual method: Enter the SM-DP+ address and activation code exactly as provided. A single character error will cause the activation to fail.

iOS 17.4 long-press method (same-device QR code): If the QR code is in an email or photo on the same iPhone, open the image in Mail, Photos, or Safari, long-press the image, and tap Add eSIM.

Step 4 — Wait for the Profile to Download

The download typically completes within a few seconds to one minute. When the status bar shows Cellular Plan Added, the profile is installed. Do not close Settings or lose your Wi-Fi connection during this step.

Step 5 — Complete the Configuration Prompts

iOS will prompt you to:

1. Set a label for the new line
2. Choose your default line for calls
3. Choose your default line for data
4. Review iMessage and FaceTime settings

Complete these prompts now, or skip them and configure each setting manually in the following sections.

Naming and Labeling Your Lines

Clear line labels make every subsequent setting easier to understand. When a call comes in, the lock screen shows the label of the line being called. When you compose an iMessage, the label appears in the send-from picker. When you review the Cellular Data settings, the labels identify which line is which.

How to Set or Change a Label

1. Go to Settings > Cellular
2. Tap the line you want to label
3. Tap Cellular Plan Label (Apple’s official UI label)
4. Type the label and tap Done

There is no fixed list of labels — you can type any name. Practical options:

The label you set appears in the iOS status bar’s SIM indicator, on the call screen, and in iMessage thread headers when switching between lines.

Setting Default Lines (Voice / Data / iMessage)

Each line assignment is configured separately. Leaving any of these at the wrong default — especially the data line — can result in unexpected charges.

Default Voice Line

The default voice line handles all outgoing calls unless you override it per-call.

1. Go to Settings > Cellular
2. Tap Default Voice Line
3. Select the line you want for outgoing calls

If you are using a travel eSIM: set your home SIM as the default voice line. Most travel eSIMs are data-only and cannot make voice calls directly. Outgoing calls on a data-only eSIM would either fail or route through a VoIP app. For the complete travel setup walkthrough, see Your First Travel eSIM: Step-by-Step Guide.

Default Line for Data

1. Go to Settings > Cellular
2. Tap Cellular Data
3. Select the line to use for mobile data

If you are using a travel eSIM abroad: select the travel eSIM here. If you leave the home SIM as the data line while abroad, the home SIM will use international roaming data, which may incur charges.

Default Line for SMS (Non-iMessage Texts)

1. Go to Settings > Cellular
2. Tap Default Voice Line (the SMS default follows the voice default on most iOS versions)

SMS messages use the Default Voice Line — there is no separate SMS line setting in iOS.

SMS sent from your device goes out on the line set here. Replies arrive on the line the original message was sent from, not necessarily the line the recipient dialed.

iMessage Send & Receive

iMessage is configured separately from the voice and SMS defaults.

1. Go to Settings > Messages > Send & Receive
2. Under You Can Be Reached By iMessage At, confirm both your phone numbers and Apple ID email appear
3. Under Start New Conversations From, select the address or number you want to use as the default sender

Recommendation: set your Apple ID email address as the default sender for new iMessage conversations. This routes iMessages over the data connection (any active line) rather than tying delivery to a specific phone number. When using a travel eSIM abroad, this ensures iMessages continue working even if your home SIM has no data roaming active.

FaceTime

1. Go to Settings > FaceTime
2. Under You Can Be Reached At, confirm both numbers and your Apple ID email are enabled
3. Under Caller ID, select the number or email to display when you initiate a FaceTime call

Allow Cellular Data Switching

Location: Settings > Cellular > Cellular Data > Allow Cellular Data Switching

When this toggle is on, iOS can automatically move data traffic to the non-default SIM if the default data SIM loses signal. This provides seamless connectivity in areas where one network has weaker coverage.

When to Turn It Off

Turn Allow Cellular Data Switching off in any situation where switching to the other SIM would cause unexpected charges:

• Traveling abroad with a travel eSIM: if the travel eSIM signal drops momentarily and the home SIM is the fallback, the home SIM begins using international roaming data. International roaming data rates apply.
• When one line has no data plan: if your second line is a voice-only plan, and cellular data switches to it, data connectivity stops or the SIM may be charged for individual data sessions depending on the carrier.

When to Leave It On

Keep Allow Cellular Data Switching on when:

• Both SIMs have valid domestic data plans and you want the device to use whichever has the stronger signal at any moment.
• You are traveling within a region where both SIMs are covered by the same or equivalent plans (for example, two domestic plans on the same network).

Switching Active Lines

Per-Call Line Selection

When making an outgoing call, you can choose which line to use regardless of the default voice setting.

1. Open the Phone app
2. Dial the number
3. Before tapping the call button, tap the line name displayed at the top of the Phone screen to switch to the other line for this call
4. Select the line you want for this call
5. Tap the call button

Alternatively, from the Contacts or Recents tab, tap the phone icon and then tap the line selector that appears before the call connects.

Switching the Data Line Mid-Use

To switch which line handles data without changing your default settings permanently:

1. Go to Settings > Cellular > Cellular Data
2. Tap the line to activate for data

This changes the active data line immediately. Turn off Allow Cellular Data Switching if you want the line to stay fixed.

Quick Access via Status Bar / Control Center

On iPhone models with a dual SIM indicator in the status bar, you can see which line is active for data at a glance. There is no single-tap toggle in Control Center for switching lines — the switch is made in Settings > Cellular.

Managing Lines (Turn Off, Remove)

Turn Off a Line Without Deleting It

Turning a line off suspends it without removing the profile. The line will not receive calls, texts, or use data while off.

1. Go to Settings > Cellular
2. Tap the line
3. Toggle Turn On This Line off

To reactivate, follow the same path and toggle it back on.

This is useful when you return home from a trip and no longer need the travel eSIM to be active — the profile stays on the device, ready to re-enable for your next trip.

Delete an eSIM

Deleting an eSIM removes the profile from the device. This is permanent — you cannot recover the profile after deletion. To use the same plan again, you will need to request a new QR code or activation code from your provider (some providers allow this at no charge; others charge for a new profile).

1. Go to Settings > Cellular
2. Tap the eSIM line
3. Scroll to the bottom and tap Delete eSIM (labeled Delete Plan when multiple plans are installed on the device)
4. Confirm deletion

Before deleting, check your provider’s reinstall policy. If they support free reinstallation via their app or a new QR code, you can delete and reinstall easily. If they do not support reinstallation, deleting the profile means losing access to that plan.

Remove a Physical SIM

To remove a physical SIM, eject the SIM tray using a SIM eject tool or a straightened paper clip. The line is removed from Settings > Cellular automatically once the tray is ejected. No in-settings action is required.

FAQ

How do I set a default data line on iPhone?

Go to Settings > Cellular > Cellular Data, then tap the line you want to use for mobile data. This sets it as the default for all data traffic. If you are using a travel eSIM abroad, select it here and turn off Allow Cellular Data Switching to prevent the device from falling back to your home SIM’s roaming data.

Can I assign a specific line to a contact on iPhone?

Yes. Open the Contacts app, tap a contact, tap Edit, scroll down to the phone number, and tap the label field next to the number. You can select which SIM line to use for calls to that contact. This setting applies to outgoing calls only — incoming calls arrive on whichever line the caller dialed.

What does Allow Cellular Data Switching do?

When enabled, iOS automatically routes data to the non-default SIM if the default data SIM loses signal. This is useful domestically but creates a roaming charge risk when traveling — if the device switches data to your home SIM abroad, that SIM’s international roaming rates apply. Turn it off at Settings > Cellular > Cellular Data > Allow Cellular Data Switching when using a travel eSIM.

How do I rename a SIM line on iPhone?

Go to Settings > Cellular, tap the line you want to rename, then tap Cellular Plan Label (Apple’s official UI label) and type a new label. Common labels include “Personal,” “Work,” “Travel,” or the carrier name. The label appears in the status bar, call screen, and iMessage thread headers.

Which iPhones support dual eSIM (two eSIMs without a physical SIM)?

iPhone 13, iPhone 13 mini, iPhone 13 Pro, iPhone 13 Pro Max, iPhone SE (3rd generation), and all later models. These can run two eSIM profiles simultaneously with no physical SIM card required. iPhone XS through iPhone 12 series support one physical SIM plus one eSIM only.

Can I turn off one SIM without deleting it?

Yes. Go to Settings > Cellular, tap the line, then toggle Turn On This Line off. The eSIM profile stays stored on your device. Turning a line off stops it from making or receiving calls and using data, but the profile remains installed and can be re-enabled at any time without reinstalling.

Related Guides

• What Is Dual SIM? — DSDS, DSDV, and DSDA explained; what mode iPhone uses
• Using Dual SIM for Travel — Line assignments, roaming charge prevention, and SMS 2FA when abroad
• How to Set Up eSIM on iPhone via QR Code — Full installation walkthrough for adding an eSIM
• What Is an eSIM? — How eSIM technology works and supported devices
• Your First Travel eSIM — Choosing and installing a travel eSIM from scratch

To compare available eSIM plans for your destination, use SimFinder Travel.

Sources:

• Use dual SIM with two nano-SIM cards or two eSIMs on iPhone - Apple Support
• Learn which type SIM your iPhone or iPad uses - Apple Support
• Set up eSIM on iPhone - Apple Support