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Understand WiFi Calling

What is WiFi Calling?

WiFi Calling allows you to make and receive calls, send text messages and MMS messages using a suitable WiFi connection, even if there is no mobile coverage. ​

You can use it anytime that your phone has a WiFi connection. It’s a great option if you have poor mobile coverage or no coverage and a WiFi connection is available.

WiFi Calling works the same way a regular cellular mobile call does using the dialling functions and address book on your phone. The difference is how the call is transmitted. WiFi Calling uses a WiFi connection to carry the services instead of the cellular network (VoLTE).​

With WiFi Calling, your call can handover between the connections while making a call.

Spark WiFi Calling services

  • You can make local calls and send texts within NZ
  • You can make calls and send texts from NZ to overseas

If you're currently located overseas or if you're using a VPN Service in NZ, you may not be able to use Spark WiFi Calling.

WiFi MMS services are not currently available.

How to activate WiFi Calling

WiFi Calling is off by default on your device.

To use WiFi calling you can toggle the feature in your device settings.

Apple phones

  1. Go to your Settings.
  2. Select Mobile settings. Depending on your phone, you may also find the setting under Mobile Data or Phone settings.
  3. Set Wi-Fi Calling to On.
  4. If you get a message asking 'Enable Wi-Fi Calling?' select Enable.

Samsung phones

  1. Go to Phone settings.
  2. Select Connections.
  3. Connect WiFi calling.
  4. Select ‘Mobile Network preferred or ‘Wi-Fi preferred (Will default Mobile Network Preferred).
  5. Note: On a Samsung phone, you can see when WiFi Calling is activated when a small icon of a phone with radio waves pop up in the notification bar at the top of the screen.

OPPO phones

  1. Go to your Settings.
  2. Select Mobile Network.
  3. Choose Select SIM.
  4. Select WiFi Calling.

Nokia phones

  1. Go to your Settings.
  2. Select Network and Internet.
  3. Select Mobile Network.
  4. Select Advanced.
  5. Select WiFi Calling.


Benefits of WiFi Calling  

  • Keep connected: Stay in touch with your friends and family from remote locations. All you need is a WiFi connection.
  • Back up connectivity: WiFi Calling helps you stay connected even if you have poor mobile coverage.  
  • Compatible: Simply check that you have a Spark approved compatible device with latest software for WiFi Calling and a WiFi connection. No need to install third party apps to use the service.
  • No extra cost: If you already have a Spark mobile plan, there is no additional cost to use WiFi Calling.
  • Convenient: It’s just like making a regular phone call. Make and receive calls the same way you currently do.
  • Make calls on Flight Mode: You can use WiFi Calling while on Flight Mode if you're connected to WiFi.

Billing information  

There is no additional monthly cost to use WiFi Calling on your mobile. Calls and texts made over WiFi Calling will be charged using calling and texting allocation in your Spark Prepaid pack or Pay Monthy plan.

Services will be charge at standard calling rates if:

  • You've used all your mobile calling allocation for the month.
  • You don't have a plan with unlimited calling or included minutes, and or texts.
  • The call-type or SMS type is not included in your plan.

In the event of excluded call-types, calls will be charged at the rates advertised by the relevant service provider.


Devices that can use Spark WiFi Calling

Not all features are available on every device , refer to our full device compatibility list


WiFi Calling generally uses around 100-120kbps bandwidth. This is only a small percentage of total bandwidth. However, if there are household members simultaneously  streaming or downloading big files on the WiFi connection, then it may result in a slight loss of voice quality on your call.

Video calls over WiFi calling will require greater bandwidth than a voice call.

Some WiFi Calling hotspots or workplaces may not allow access for WiFi Calling, for example hotels or corporate hotspots.


As Spark may not have control over the WiFi connection the mobile device is using, we cannot guarantee the quality of the WiFi call.

The strength of the wireless signal within a building, or simultaneous activities using the connection, can impact the voice experience.

You can, as long as you are on a Spark Fixed or Wireless Broadband connection and have used your monthly allocation. If your service has been throttled, then you may voice experience may be impacted.  

Since WiFi calling can be used on WiFi connections that are outside Spark’s control, you will need to check directly with the service provider your connection is with to see if WiFi Calling will work in this situation.  

If you move into an area with sufficient mobile network coverage, then your call will continue without interruption.

If you move into an area with is no sufficient mobile network coverage, then the call will drop, once the signal quality of the WiFi connection becomes too weak.

If you've turned on WiFi Calling on your device, your phone will try to use mobile network coverage first, even if you have WiFi Calling available.

If the network detects poor or no mobile coverage and there is a WiFi connection available, the call will transmit by WiFi Calling. Some devices will give you the option to select a preferred option.

When WiFi calling is enabled on your device, the device will be set to preferred cellular as the default option.

Yes, but when making an emergency call in NZ, mobile is always preferred.

This includes using other mobile providers networks in NZ to transmit the call. If there is no coverage, emergency calls can be made by using WiFi Calling.

Calling Emergency Services from overseas is not available, and any 111 call attempted from overseas will not connect.

If you are using WiFi calling in an area without mobile coverage, you won’t receive any Civil Defence mobile alerts.

In the event there is no mobile coverage, WiFi calling is enabled by a Fixed or Wireless Broadband connection. If there is a power cut affecting the WiFi connection that is being used, then WiFi calling will not work. 

If you're using WiFi Calling in an area without Spark mobile coverage, you won’t receive any Civil Defence emergency mobile alerts.

If you’re using WiFi Calling and your phone has Spark mobile coverage, you’ll receive these alerts as usual.


WiFi Calling is enabled by a Fixed broadband connection. If there is a power cut affecting the equipment used for your WiFi Calling, then WiFi Calling will not work. 


A  ‘Spark NZ WiFi Calling’ icon will likely appear at the top of your screen when the call is active.

Not all device types will display a WiFi call icon. Or you can check your phone’s mobile settings to see if WiFi calling is enabled. 

If you move between a WiFi connection and cellular connection during the call, your call will continue. You may not always know if you are using cellular or WiFi calling. 

In general, you're able to use WiFi Calling when you have a compatible device and a WiFi Connection.

There are some factors where WiFi Calling may not be supported on the WiFi network you're connected to, such as:

  • Some internet providers either in NZ or overseas may block WiFi calling.
  • Enterprise or public WiFi connections may not be configured to let you to use WiFi Calling.
  • Some networks may be set up with specific firewall settings that block WiFi Calling.
  • Spark WiFi calling is not available in overseas locations .

If you have a Spark Fixed (Fibre/ADSL/VDSL) or wireless broadband connection, there is no extra charge for WiFi Calling and it won’t count against your data cap.

If you're using a non-Spark broadband connection, then you should check with your service provider for any broadband usage consumption or charges that may apply for using WiFi Calling.

WiFi Calling uses approximately 1-5MB /minute of data for a standard voice call, which is a small amount.

Video calling will consume approximately 6-8MB/minute depending on the video resolution. The actual data usage of your WiFi call will vary.

VoLTE is referred to as Voice over 4G LTE network, which is the latest technology for voice quality. This enables you to use your data for browsing while on a call and allows greater capabilities for video calling and file-sharing.

VoWiFi uses the WiFi network to make calls on HD using the VoLTE platform so you can make a call regardless of your mobile strength.

You must have VoLTE to use WiFi Calling, but you don't need WiFi Calling to use VoLTE. 

Yes, if you're using VoLTE and have enabled WiFi Calling on your phone settings, you'll be able to make and receive calls over a Fixed Broadband connection.

If you have a dual SIM you'll need to check the settings for your primary or secondary number, depending on the connection you're wanting to use for WiFi Calling. 

Calling features available on VoLTE calling can be used if you have WiFi calling enabled.

In some instances, you'll need to change back to cellular functions to change some of your settings,  eg. call forwarding and voicemail. 

No. WiFi video calling is not available on Apple devices. 

If you're unable to make and receive calls, you might not be in a cellular coverage or WiFi coverage area.

Other reasons may include incorrect call settings such as WiFi Calling being switched off in your mobile phone settings. Or, VoLTE may not yet be enabled on your phone to use the WiFi Calling service.

No, this will not be charged if you have an active plan with allowance to be used. Any shortcode or premium messaging will be charged at standard rates.

Learn more about premium text services

VoWiFi makes use of IPSEC to securely connect back to Spark’s infrastructure. Most firewalls and broadband connections don't need modification, and when connected via Wi-Fi should seamlessly support Spark’s Wi-Fi calling service.

However, some corporate firewalls may need modification to allow connectivity to our infrastructure, specifically to the following IP/PORTs:

IP addresses



  • UDP/500
  • UDP/4500

Please consult with your IT department if that is the case.

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