Wi-Fi Calling on Oppo: How to Enable VoWiFi in 5 Minutes

Calls by Wi-Fi (VoWiFi) on smartphones Oppo allow you to make and receive calls even without a mobile network—a stable internet connection is sufficient. This feature is especially useful in areas with poor 4G/5G coverage, such as basements, country houses, or tall buildings where the operator's signal doesn't reach. However, not all models Oppo support VoWiFi, and the settings depend on the firmware and mobile operator tariff.

In this article you will find Current methods for enabling VoWiFi for Oppo Reno, Find, A-series, and other models, including hidden settings for older versions of ColorOS. We'll also discuss why the feature may not work despite being configured correctly, and what to do if your carrier doesn't support the technology. If your smartphone doesn't see the "Wi-Fi Calling" option in the menu, don't worry: it may simply need to be "unlocked" through the engineering menu.

Checking VoWiFi support on your Oppo model

Before setting up Wi-Fi calling, make sure your smartphone is Oppo supports this feature. VoWiFi (Voice over Wi-Fi) technology requires hardware and software compatibility. Here are the key points:

• 📱 Models with official support: Oppo Find X5 Pro, Reno8 Pro, Reno7, A96, A76 and newer (2021–2026). Most flagship and mid-range devices on ColorOS 11+ have VoWiFi out of the box.
• 🚫 Models without support: budget devices (Oppo A16, A54) and devices older than 2020 (Reno3, Find X2) are often missing functions. The exception is firmware from third-party developers (for example, LineageOS).
• 🔄 Operator dependencyEven if a smartphone supports VoWiFi, the feature will only work with operators that have activated it. In Russia, this MTS, Beeline, Megaphone And Tele2 (but not all tariffs!).

To find out for sure whether yours supports Oppo VoWiFi, check:

1. Go to Settings → SIM cards & mobile networks → [select SIM] → Wi-Fi callingIf there is no item, there is no support (or a firmware update is required).
2. Use the app Network Signal Guru (available in Play Market): in the section VoLTE/VoWiFi The support status will be indicated.

⚠️ Attention: On some models Oppo (For example, Reno4) The VoWiFi option is hidden and is activated only after updating to ColorOS 12+If your smartphone was released before 2021, check for updates in Settings → Software Update.

Preparing your smartphone: updating the firmware and SIM card

If your model Oppo If your phone supports VoWiFi, but the option isn't visible in the settings, the problem may be due to outdated firmware or an incompatible SIM card. Follow the checklist:

Update ColorOS to the latest version

Make sure your SIM card supports VoLTE/VoWiFi (nano-SIM 4G+)

Activate the VoLTE service with your operator (sometimes you need to call support)

Restart your smartphone after the update-->

Firmware update:

1. Go to Settings → Software Update.
2. Click "Check for Updates" and wait for the latest version to download. ColorOS.
3. If an update is found, install it (requires at least 50% battery charge).

After updating, check for the presence of the item Wi-Fi calling in the SIM card settings. If it's not there, try resetting the network settings:

Settings → Advanced → Reset → Reset network settings

Checking the SIM card:

• VoWiFi only works with nano-SIM formats that support VoLTE.
• If you are using an old SIM card (manufactured before 2018), replace it at the operator's office.
• For MTS And Beeline check service activation VoLTE/VoWiFi in your personal account or via USSD command *111*467# (for MTS).

⚠️ Attention: On smartphones Oppo With two SIM cards, VoWiFi can only work on one of them (usually the one installed in the slot) SIM1). Check the priority in the settings.

Step-by-step instructions: how to enable VoWiFi on Oppo

If all conditions are met, proceed to activating the function. The instructions are suitable for ColorOS 11–14:

1. Open Settings and go to the section SIM cards and mobile networks.
2. Select a SIM cardfor which you want to activate VoWiFi (if there are two of them).
3. Find the "Wi-Fi Calling" option** (may be called Wi-Fi Calling or VoWiFi).
4. Activate the switch and confirm the connection if required.
5. Select operating mode:
   • Wi-Fi only — calls will only be made via the Internet (suitable for areas without a network).
   • Wi-Fi is preferred — the smartphone will use Wi-Fi if the mobile network signal is weak.
   • Mobile network is preferred — VoWiFi is activated only when there is no coverage.

Once activated, an icon will appear in the status bar. VoWiFi or Wi-Fi Calling (Depending on model). To check the function:

1. Connect to Wi-Fi.
2. Turn on Airplane mode (will turn off mobile network).
3. Try making an outgoing call - if the connection is established, VoWiFi is working.

Troubleshooting: VoWiFi won't turn on or isn't working

If Wi-Fi calling doesn't work after setup, check the following:

Problem	Possible cause	Solution
There is no "Wi-Fi Calling" option in the settings.	Outdated firmware or model does not support VoWiFi	Update ColorOS or check model compatibility
VoWiFi turns on, but calls don't go through.	The operator does not support the function or has blocked it for your tariff.	Call the operator's support and clarify the conditions.
Calls are dropped or the connection quality is poor	Weak Wi-Fi signal or congested network	Connect to a different Wi-Fi network or reboot your router
VoWiFi only works on one SIM card.	Oppo Dual SIM Smartphone Limitations	Swap the SIM cards (try SIM1 slot)

Additional diagnostic methods:

• 📶 Check your Wi-Fi signal strength: if the level is lower -70 dBm, VoWiFi may not work. Use the app WiFi Analyzer for analysis.
• 🔧 Reset network settings: Settings → Advanced → Reset → Reset network settings.
• 📱 Install alternative software for calls (for example, Google Phone), which supports VoWiFi on uncertified devices.

How do I check VoWiFi support using the engineering menu?

Open the Phone app and type ##4636##. Go to the section Phone information and find the line VoWiFi provisioned. If the value 1 — the function is supported, 0 - No.

VoWiFi on Oppo with custom firmware

If your Oppo does not support VoWiFi out of the box, but the hardware is capable of it (for example, Find X2 or Reno3 Pro), you can try activating the feature via custom firmware. This method is suitable for advanced users and requires unlocking the bootloader.

Step-by-step instructions:

1. Unlock the bootloader through the official website Oppo (instructions for your model are on the forum) 4PDA).
2. Install a custom recovery (TWRP).
3. Flash the firmware based on AOSP (For example, LineageOS or Pixel Experience), where VoWiFi is supported by default.
4. After installation, check for the option in Settings → SIM cards → Wi-Fi calling.

⚠️ Important:

• Custom firmware may cause problems ColorOS-features (for example, camera or gestures).
• Some operators block VoWiFi on uncertified devices.
• Before flashing, make a backup of your data using TWRP.

⚠️ Attention: Installing custom firmware will void the warranty. Oppo and may brick the device. If you're unsure of your skills, consult a professional.

VoWiFi vs. VoLTE Comparison: Which is Better for Oppo?

Many users are confused VoWiFi (Wi-Fi calling) and VoLTE (4G calls). While both technologies improve connection quality, they operate differently. Here are the key differences:

When to use VoWiFi?

• 🏠 At home or in the office, where Wi-Fi is more stable than a mobile network.
• 🚇 In the subway, basements, and other places without 4G coverage.
• 🌍 While roaming (if your operator doesn't block VoWiFi).

When is VoLTE best?

• 🚗 On the move (switching between towers is smoother than between Wi-Fi hotspots).
• 📶 In places with good 4G/5G coverage.
• 🔋 If you need to save battery power (VoLTE is optimized for mobile networks).

Security and privacy when using VoWiFi

Wi-Fi calls are transmitted over the internet, which raises security concerns. Here's what you need to know:

How is data protected?

• 🔒 VoWiFi uses the protocol IPSec or SRTP for voice encryption.
• 🛡️ Operators (eg. MTS) apply additional encryption at the network level.
• 🌐 When connecting to public Wi-Fi (cafes, airports), the risk of interception is higher - use a VPN.

Risks and how to avoid them:

• 🕵️ Wiretapping: Unlikely due to encryption, but possible when using vulnerable access points.
• 📍 Location leak: The operator can see your IP address (just like with a regular Internet connection).
• 💳 Fraud: Attackers can impersonate a VoWiFi base station to intercept calls (rare, but possible).

Safety recommendations:

1. Do not connect to unknown Wi-Fi networks for calls.
2. Use a VPN (eg. ProtonVPN or NordVPN) when making calls via public networks.
3. Update your firmware regularly Oppo — VoWiFi vulnerabilities are fixed in new versions.

⚠️ AttentionIf you use VoWiFi for corporate calls, check with your company's IT department to ensure you're allowed to connect to the corporate Wi-Fi network. Some organizations block VoWiFi due to data leakage concerns.

Oppo VoWiFi FAQ: Answers to frequently asked questions about VoWiFi

My Oppo doesn't see the "Wi-Fi Calling" option. What should I do?

First check:

1. Does your model support VoWiFi (see list above).
2. Is the firmware updated to the latest version? ColorOS.
3. Is the service activated by the operator (sometimes sending a USSD command is required).

If everything is fine but the option is still missing, try resetting your network settings or contacting support. Oppo.

VoWiFi works, but the connection quality is poor. What's the problem?

The reasons may be as follows:

• Weak Wi-Fi signal (check the speed via Speedtest).
• Congested network (especially during rush hour).
• Problems on the operator's side (call support).

Solution: Reconnect to a different Wi-Fi network or use a cable connection (if your router supports it) Wi-Fi 6).

Can I use VoWiFi while roaming?

Yes, but with some reservations:

• MTS And Megaphone support VoWiFi while roaming, but may incur additional charges.
• Beeline And Tele2 The function is often blocked abroad.
• Check the tariff terms in your operator's personal account.

Will VoWiFi work on Oppo with dual SIM?

On most models Oppo VoWiFi only works on one SIM card (usually on SIM1). To activate the function for the second SIM:

1. Swap the SIM cards.
2. Check if the second SIM card supports VoLTE/VoWiFi (it may need to be replaced).

How to disable VoWiFi on Oppo?

To disable Wi-Fi calling:

1. Go to Settings → SIM cards & mobile networks → [select SIM] → Wi-Fi calling.
2. Turn off the switch.
3. Restart your smartphone if the VoWiFi icon remains in the status bar.