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Wi-Fi Calling on Samsung S23, S24 and S25: eSIM Setup and Troubleshooting

Wi-Fi Calling on Samsung S23, S24 and S25: eSIM Setup and Troubleshooting

Last updated: April 2026

Wi-Fi Calling is the feature that turns a poor-signal office into a workable one. For business users on Samsung, it is a must-enable. The wrinkle in 2026 is that Galaxy S24 and S25 support dual eSIMs, and many users have one personal and one work eSIM on the same phone. Samsung does not always make it obvious which eSIM is using Wi-Fi Calling, which is why "how to switch which eSIM is used for Wi-Fi Calling on Samsung" is one of the most-searched phrases on this topic.

This guide covers the whole lot: enabling Wi-Fi Calling, dual eSIM setup, switching which eSIM uses it, and the most common problems we see on business accounts.

Which Samsung Phones Support Wi-Fi Calling in the UK

All current-generation Galaxy S phones support Wi-Fi Calling on all four major UK networks when the feature is provisioned on the line:

  • Galaxy S23, S23+, S23 Ultra
  • Galaxy S24, S24+, S24 Ultra
  • Galaxy S25, S25+, S25 Ultra

Wi-Fi Calling must be enabled BOTH on the device (by you) and on the network account (by the carrier). On EE and Vodafone it is normally on by default. On O2 Business and Three Business it sometimes needs a call to business support to provision.

How to Turn On Wi-Fi Calling on Samsung

The menu path is identical across S23, S24 and S25:

  1. Open Settings
  2. Tap Connections
  3. Tap Wi-Fi Calling
  4. Toggle Wi-Fi Calling to ON
  5. You may be asked to confirm an address (for 999 calls) — enter your real work address
  6. The status bar will show a small Wi-Fi icon with a phone handset when active

Alternatively on One UI 6 and 7:

  1. Open the Phone app
  2. Tap the menu (three dots, top right)
  3. Tap Settings
  4. Tap Wi-Fi Calling
  5. Toggle to ON

When Wi-Fi Calling is active and the phone is on Wi-Fi, the status area often shows "VoWiFi" or the carrier name with a Wi-Fi tag (e.g. "EE VoWiFi"). Calls and texts will route over Wi-Fi automatically when cellular signal is weak.

What Wi-Fi Calling Does (and Doesn't Do)

Wi-Fi Calling:

  • Routes voice calls over your Wi-Fi when cellular is weak
  • Routes SMS/MMS over Wi-Fi when cellular is weak
  • Uses your UK allowances — Wi-Fi Calling from abroad to a UK number is charged as a UK call, not a roaming call

Wi-Fi Calling does NOT:

  • Make data faster — data always uses the better of cellular or Wi-Fi regardless
  • Work over all Wi-Fi networks — captive portals and some corporate firewalls block it
  • Work if the line is not provisioned on the carrier side
  • Guarantee 999 access — which is why Samsung prompts you for a physical address

Dual eSIM on Samsung S24 and S25

Galaxy S24+, S24 Ultra, S25, S25+ and S25 Ultra support two active eSIMs plus the physical SIM slot, giving up to three lines of which two can be active at once. S24 base model is eSIM + nano-SIM only. S23 series also supports one eSIM + one nano-SIM.

On Samsung the two active lines are managed in Settings > Connections > SIM manager. For each line you can set:

  • Preferred SIM for calls — which line dials by default
  • Preferred SIM for messages — which line sends SMS by default
  • Preferred SIM for mobile data — which line provides internet
  • Labels — rename the SIMs to Work and Personal
  • Colours — distinguish visually in the dialler

You can also allow either SIM to answer calls, which is the usual business setup: make outbound calls from the work line, but receive on both.

How to Switch Which eSIM Is Used for Wi-Fi Calling on Samsung

This is the thing that catches most dual-SIM business users out. Wi-Fi Calling is configured PER SIM, not globally. On Samsung S23, S24 and S25:

  1. Open Settings
  2. Tap Connections
  3. Tap Wi-Fi Calling
  4. If you have multiple SIMs, you will see a SIM chooser at the top, or the Wi-Fi Calling screen will show settings for each SIM on a tabbed view (depending on One UI version)
  5. Tap the SIM you want to configure (e.g. your work eSIM)
  6. Toggle Wi-Fi Calling ON for that specific SIM
  7. Repeat for the second SIM if you want it on there as well

Alternatively on One UI 7 (S25 default):

  1. Settings > Connections > SIM manager
  2. Tap the SIM you want to configure (e.g. "Work")
  3. Scroll to Call preferences
  4. Tap Wi-Fi Calling — toggle ON for that SIM
  5. Back out and repeat for the other SIM if needed

Which SIM should be used for Wi-Fi Calling?

  • On any line where you need reliable calls in low-signal locations (office, basement, a specific client site), enable Wi-Fi Calling.
  • For lines you only use outdoors with cellular signal, it is optional.
  • On a business line that is provisioned for Wi-Fi Calling, always turn it on — it costs nothing extra and saves dropped calls.

Note: Some networks (historically O2 and Three) did not support simultaneous dual-SIM Wi-Fi Calling on the same handset — you could only use it on one SIM at a time. This is being progressively lifted in 2025-26. Check with the carrier if your second SIM refuses to keep Wi-Fi Calling enabled.

eSIM Setup on Samsung

To add a new eSIM to an S23/S24/S25:

  1. Settings > Connections > SIM manager
  2. Tap Add eSIM
  3. Either:
    • Scan carrier QR code — hold the phone over the QR
    • Enter activation code manually — if the carrier gave you a text string
    • Search for available plans — for carriers supporting in-device plan purchase (rare on UK business)
  4. The phone downloads the profile (takes 10-30 seconds)
  5. Name the SIM (e.g. Work), pick a colour, confirm

To transfer an eSIM between Samsung devices, use Smart Switch on the new device and pick "Phone" as the source. This works for most UK carriers' eSIMs. For carriers that block it, you will need a new QR code from the carrier.

Common Wi-Fi Calling Problems on Samsung

Wi-Fi Calling toggle turns itself off. Nearly always a provisioning issue. Call the carrier business support line and ask them to enable Wi-Fi Calling / VoWiFi on that specific MSISDN. Reboot the phone after they confirm it is on.

Wi-Fi Calling only works on one SIM, not the other. Confirm with the carrier of the second SIM that Wi-Fi Calling is provisioned. Then check in SIM manager that the setting is enabled per-SIM.

"Wi-Fi Calling" shown but calls still use cellular. The phone only prefers Wi-Fi Calling when the cellular signal is below a certain threshold, or when you are on a call that's failing on cellular. If cellular signal is strong, the phone may stay on cellular and that's by design.

Quality issues on Wi-Fi Calls. Usually VPN is interfering. Turn VPN off temporarily. Also check your Wi-Fi has at least 3 Mbps sustained — congested or shared Wi-Fi will degrade calls.

Cannot call 999 over Wi-Fi Calling. In most UK setups 999 over Wi-Fi Calling works, but the carrier uses the registered address to route. Make sure the address in Wi-Fi Calling settings is real and current.

Abroad, Wi-Fi Calling not available. Some networks disable Wi-Fi Calling abroad intentionally. Others allow it in specific countries. Check with the carrier. If allowed, it is an enormous cost saving as calls to UK numbers from abroad over Wi-Fi Calling are charged as UK calls.

Business Setup Checklist

For every new Samsung S23/S24/S25 you hand to a business user:

  1. eSIM activated, correct default set for calls / messages / data in SIM manager
  2. Wi-Fi Calling enabled per SIM — both work and personal if applicable
  3. Emergency address entered
  4. Preferred network type set to "5G/LTE/3G/2G auto"
  5. Data roaming OFF by default
  6. Wi-Fi Assist equivalent (Samsung's "Switch to mobile data" option) reviewed
  7. VoLTE enabled (Settings > Connections > Mobile networks > VoLTE) — required for clean Wi-Fi Calling on most networks
  8. Carrier business support contacted to confirm Wi-Fi Calling is provisioned if toggle will not stay on

VoLTE and Wi-Fi Calling — Why They Go Together

VoLTE (Voice over LTE) must be on for Wi-Fi Calling to work reliably on most UK networks. The Wi-Fi Calling system handover depends on VoLTE being available when Wi-Fi drops to cellular.

To enable VoLTE:

  1. Settings > Connections > Mobile networks
  2. Toggle VoLTE calls (or "Enable 4G calling") ON per SIM

If the option is missing, the phone or the line does not support VoLTE. Call business support.

What We Do on Samsung Business Quotes

On every Samsung S-series business quote we:

  1. Compare EE, Vodafone, O2 and Three for the user's data and travel profile
  2. Confirm Wi-Fi Calling provisioning with the chosen carrier before port-in
  3. Advise on single-SIM vs dual-SIM handset SKUs where there is a price difference
  4. Offer to supply pre-configured handsets for larger rollouts

Free quote here.

Frequently Asked Questions

Q: How do I turn on Wi-Fi Calling on Samsung S24?

Settings > Connections > Wi-Fi Calling > toggle ON. Alternatively, Phone app > three-dot menu > Settings > Wi-Fi Calling.

Q: How do I switch which eSIM is used for Wi-Fi Calling on Samsung?

Settings > Connections > Wi-Fi Calling. On One UI 6 and 7, you can toggle Wi-Fi Calling separately for each SIM on the Wi-Fi Calling screen, or via SIM manager > tap the SIM > Call preferences > Wi-Fi Calling.

Q: Does Samsung S25 support dual eSIM Wi-Fi Calling at the same time?

Yes on EE and Vodafone. O2 and Three have historically restricted simultaneous dual-SIM Wi-Fi Calling on the same handset — check with business support before relying on it.

Q: Why does Wi-Fi Calling on my Samsung keep turning off?

Usually because the line is not provisioned for Wi-Fi Calling on the carrier. Call business support and ask them to enable Wi-Fi Calling / VoWiFi on the line, then reboot.

Q: Do I need VoLTE on to use Wi-Fi Calling?

In practice yes, on all UK networks. Enable VoLTE in Settings > Connections > Mobile networks > VoLTE calls.

Q: Can I use Wi-Fi Calling abroad on Samsung?

Sometimes. EE and Three allow it to UK numbers from many countries, charged as UK calls. O2 and Vodafone vary. Confirm with your business support line before you travel.

Related Reading

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