Questions about VoLTE and VoWiFi

This handy guide helps you make sense of what VoLTE and VoWiFi is, why it is important and what you can use it for.


VoLTE (Voice over LTE) is an advanced technology that delivers high-quality life-like sound across the 4G network. With Proximus VoLTE you experience ultra-clear voice quality and reduced background noise everywhere in Belgium. Conversations will sound more natural, almost as if the person at the other end of the phone call is right next to you.

Moreover, when combining VoWiFi with VoLTE, your phone will automatically switch over from a Wi-Fi signal to a mobile signal (4G), so your call won’t cut off if you lose your Wi-Fi signal. This is not possible when you’re calling over Wi-Fi with a separate app such as Skype, WhatsApp, etc. Calling or sending text messages is currently not yet available via 5G.

When calling over LTE, you don't use any data, just call minutes.

To use VoLTE, you need a Proximus mobile phone subscription and a compatible device with the latest software. The VoLTE option must be activated on your mobile subscription in order to use VoLTE. At the moment, you can make calls over 4G on:

  • Samsung: Galaxy S5, Galaxy S6, Galaxy S6 edge, Galaxy S6 edge+, Galaxy S7, Galaxy S7 edge, Galaxy S8, Galaxy S8+, Galaxy J5, Galaxy A3 2016, Galaxy A5 2016, Galaxy A3 2017, Galaxy A5 2017, Galaxy Xcover 4, Galaxy J3 2017, Galaxy J5 2017, Galaxy J7 2017, Galaxy Note 8, Galaxy A8 2018, Galaxy S9 and Galaxy S9+, Galaxy A6, Galaxy A6+, Galaxy J6, Galaxy Note 9, Galaxy J4+, Galaxy A7 2018, Galaxy A9 2018, Galaxy S10e, Galaxy S10, Galaxy S10+, Galaxy A10, Galaxy A20e, Galaxy A40, Galaxy A50, Galaxy A70, Galaxy Xcover 4s, Galaxy Note10, Galaxy Note10+, Galaxy S10 Lite, Galaxy A71, Galaxy Xcover Pro, Galaxy A51, Galaxy Z Flip, Galaxy S20, Galaxy S20+, Galaxy S20 Ultra 5G, Galaxy A41, Galaxy A21s, Galaxy Note20 5G, Galaxy Note20 Ultra 5G, Galaxy S20 5G, Galaxy S20+ 5G, Galaxy S20 FE 5G, Galaxy Z Fold 2 5G.
  • Apple: iPhone 6, iPhone 6 plus, iPhone SE, iPhone 6s, iPhone 6s plus, iPhone 7, iPhone 7 plus, iPhone 8, iPhone 8 plus and iPhone X, iPhone Xs, iPhone Xs Max, iPhone Xr, iPhone 11, iPhone 11 Pro, iPhone 11 Pro Max, iPhone SE (2020), iPhone 12, iPhone 12 mini, iPhone 12 Pro, iPhone 12 Pro Max.
  • Huawei: P10, Mate 10 Pro, P smart, P20 lite, P20 and P20 Pro, Mate20 lite, Mate20, Mate20 pro, P smart 2019, P30 lite, P30, P30 Pro, Nova 5T, P30 lite new edition.
  • Sony: XZ Premium, XZ1, XZ1 Compact, XA2 and XZ2, Xperia L2, Xperia XZ2 Compact, Xperia XA2 plus, Xperia XZ3
  • Other devices: LG: K11, G7 Fit, G7 ThinQ, V40 ThinQ, K30, K40, Q60, K40S.  Nokia: K11, G7 Fit, G7 ThinQ, V40 ThinQ, K30, K40, Q60, K40S. OnePlus: K11, G7 Fit, G7 ThinQ, V40 ThinQ, K30, K40, Q60, K40S. Oppo: Find X2 Pro 5G

Want to check whether you have the latest software on your device? Check out our step by instructions for your deviceNew window.

If your device is compatible, VoLTE must be activated on your device. This is how to make sure it is:

  • Android: go to Settings > Connections > Mobile networks> and move the slider next to VoLTE calls to the right to enable the option or to the left to disable it.
  • iOS: go to Settings > Cellular > Cellular Data Options and check or uncheck Voice & Data.

Do you want to use a VPN application? Then in some cases you have to temporarily disable VoLTE.


Voice over Wi-Fi (VoWiFi) enhances your reachability for calls and text messages deep into a building where you have Wi-Fi, even when there’s no mobile signal at all. In fact, VoWiFi allows you to call or text from any location where your device is connected to a Wi-Fi network in Belgium. For quality reasons, this service is not available while traveling abroad.

To use VoWiFi, you need a Proximus mobile phone subscription and a compatible device that supports VoLTE and VoWiFi with the latest software. At the moment, you can make calls via VoWiFi on:

  • Samsung: Galaxy S20, S20+, S20 Ultra, S20 Ultra 5G, S20 5G & S20+ 5G.
    Coming soon: Galaxy S10e, S10, S10+, S10 Lite, A70, Note10, Note10+, Note10 lite, A71, Xcover Pro, A51, Z Flip, S20 4G FE, Note20 5G, Note20 Ultra 5G, Z Fold 2 5G, A42 5G, S21 5G, S21+ 5G, S21 Ultra 5G, A32 5G, A32 4G, Xcover 5, M12 & M21.
  • Apple: iPhone SE, 6s, 6s plus, 7, 7 plus, 8, 8 plus, X, Xs, Xs Max, Xr, 11, 11 Pro, 11 Pro Max, SE (2020), 12, 12 mini, 12 Pro & 12 Pro Max.

If your device is compatible, VoWiFi must be activated on your device. This is how to make sure it is:

  • Android: open the phone app and tap More > Settings > Calls and activate the Call via wifi option.
  • iOS: turn on Wi-Fi calling in Settings > Phone > Calling via wifi

Want to check whether you have the latest software on your device? Check out our step by step instructions for your deviceNew window.

You have the latest software, but you cannot use VoWiFi on iOS? Check the version of the provider settings on your iPhone. The minimum version to be able to use VoWiFi is Proximus 45.0. For this, go to Settings > General > Info and check the provider settings.

If an update of the provider settings is available, an pop-up will be shown to install it after a waiting period.

Once the option is activated and your mobile is set up correctly, your mobile will choose to make a Wi-Fi call if your mobile coverage is weak or not existing. In other words, cellular mobile calls will by default be preferred to Wi-Fi calls. Your call will return to the mobile network if the Wi-Fi network signal becomes too weak or is cut off.

When you make a Wi-Fi call with a Samsung, a small logo appears in the upper left corner of your smartphone (to the left of the Wi-Fi network sign), representing a small telephone handset

No additional costs are charged for the use of VoWiFi technology. Calls and text messages are charged according to the bundles within your price plan and the destination that can be a national, international or premium number. A VoWiFi call/text message is billed in the same way as a normal call/text message over the mobile network (2G, 3G, 4G).

VoWiFi requires a strong and reliable Wi-Fi connection for the best possible audio quality. The Wi-Fi Booster offers a solution in case of your Wi-Fi connection is of a lesser quality.

The number of users and activity (e.g. streaming video) on a Wi-Fi network can also affect audio quality. A network with many users, such as a public Wi-Fi hotspot, may cause audio quality issues even if the network signal is strong. Multiple factors can be the cause of poor audio quality.

Via VoWiFi you can also make emergency calls.

You are required to provide your location details when calling an emergency number and this was previously only possible via our mobile network. Proximus has ensured that this is now also possible via VoWifi.

  • Your personal firewall blocks calls over Wi-Fi: you are in a place with very poor mobile coverage, you are connected to the available Wi-Fi network, your Wi-Fi calls are active on your smartphone, you have the latest software version on your device and yet you cannot make calls. Make sure that your (personal) Firewall is not the cause: the outgoing traffic goes through the UDP ports 500 and 4500 and make sure that your Firewall does not block it. If this doesn't seem to work yet, dig deeper into your firewall and check the MTU settings. MTU stands for "Maximum Transmission Unit" and for IPv4 must be 1500 bytes, for IPv6 the value is 1800 bytes.
  • I use a foreign DNS on my B-box. Does this work? You must have a Belgian IP address to be able to use calling via Wi-Fi.
  • Foreign operators don’t allow their customers to use VoWiFi when they travel outside their home country. This means that your foreign visitors probably can’t call indoor. With Mobile Coverage Extender, they can call.
  • Mobile Coverage Extender is an open network (no password needed).
  • Less guarantee of good voice quality with VoWiFi.
  • Currently limited number of devices available for VoWiFi.
More info on the Proximus Mobile Indoor Coverage services can be found on

VoWiFi for companies

You must open ports 500 and 4500 on your firewall to allow UDP traffic.

Wi-Fi infrastructure requirements for Wireless Data in business areas are not the same as for VoWiFi:

  • All areas need to be covered (also elevators, corridors, parking lots, etc.) Often these areas are not Wi-Fi covered.
  • A VoWiFi design requires a multitude in number of access points versus a data-only design (x 2 or 3) – propagation of mobile 2G/3G/4G is significantly better than for Wi-Fi.
  • A good VoWiFi experience requires a modern Wi-Fi network supporting a whole set of standards:
    • 802.11r: for fast roaming (fast Wi-Fi login).
    • 802.11k: intelligent neighbor awareness for fast exchange of Wi-Fi access points' information for moving devices.
    • 802.11v: device steering to optimal access point.
    • Band-steering: pushing devices to the best Wi-Fi bands.
    • DFS supported: Dynamic Frequency Selection (DFS) are extensions to the 802.11 standard that specify mechanisms allowing Wi-Fi devices to use 5 GHz channels that are shared with radar systems.

Conclusion: some Wi-Fi networks might already be VoWiFi-ready, but lots need to be significantly extended.

Access rights

Wi-Fi access in a company or other (public) place is often linked to a login/password:

  • Access for Wi-Fi Calling should be seamless and intuitive, without any action of the user.
  • Despite the use of EAP-SIM authentication, and other ways of automation, this remains not always fully transparent on all locations where Wi-Fi is present.

Mainly for visitors, customers, consultants, etc., in a company this might be time-consuming to always have to log in.

Security and LAN and internet connectivity aspects
  • Is your company ready to open up its LAN/WLAN to all company devices including those of visitors, customers, consultants, etc.?
  • Is your company ready to also provide open internet access for these users’ data?
  • Is your company ready to implement and manage all Quality of Service aspects on their LANs to ensure a good user experience and thus prioritize this traffic over other company traffic?
  • Is your company ready to increase its bandwidths for connectivity to the internet to route this VoWiFi (and inherent data) traffic?

Conclusion: guaranteeing a good user experience, preserving one’s own data experience and capacity and implementing security requires extra cost and effort.

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