Wi-Fi Calling on Android: how to turn it on and check if your phone supports it

Can an Android phone use Wi-Fi Calling, and what do you need?

Yes, if the phone runs Android 6.0 or later, the model supports VoWiFi, and your SIM's carrier has switched the service on for your number. You turn it on in the SIM or call settings and set Wi-Fi as the preferred route.

Wi-Fi Calling, technically VoWiFi, carries the voice of your normal mobile number over a Wi-Fi internet connection instead of the carrier's radio signal. The phone builds an encrypted IPsec tunnel to a carrier gateway called the ePDG and registers with the same IMS core that VoLTE uses. The person you call sees your usual number, you install no app, and they do not need any app either. The standard comes from 3GPP, and the GSMA sets the minimum feature set in its IR.51 profile.

All four of these must be in place before the menu appears and calls actually go through:

• Phone: Android 6.0 or later, with a modem and firmware that support VoWiFi for your carrier. Grey-import phones or phones running another region's firmware may lack the menu even when the hardware can do it.
• SIM: a physical SIM or eSIM that can already make and receive normal calls, active in the phone.
• Carrier: the carrier must enable Wi-Fi Calling for that number. Some do it automatically, others need a request first; AIS on Android, for example, asks you to dial *399*1#.
• Network: a Wi-Fi connection with working internet that does not block UDP ports 500 and 4500, which the tunnel to the ePDG needs.

Start with the basics: what Wi-Fi Calling is and how it works

How do you check whether your Android phone supports Wi-Fi Calling?

There is no single list of Android models that work on every carrier, because support depends on the pairing of phone model and carrier. Check in this order, from quickest to most precise.

1. 1Check the Android versionGo to Settings > About phone. Below Android 6.0 there is no built-in Wi-Fi Calling. Almost every phone sold in Thailand today clears this bar.
2. 2Look for the menu in SettingsOpen Settings and search for Wi-Fi calling, Wi-Fi Calling, Make calls using Wi-Fi or VoWiFi. A switch under your number's SIM menu means the phone and carrier match at least at the menu level.
3. 3Check the carrier's device listAIS points customers to its supported-model checker at ais.th/4g/vowifi. NT Mobile lists models on its service page, such as OPPO A57, A77, A96, Reno7, Reno8 Pro 5G, Find X5 Pro 5G, Xiaomi 11 Lite 5G, 11T Pro, Note 10 Pro, Redmi 9 and vivo X60 Pro. True-dtac has no single list and says the phone must support the feature and run its latest software.
4. 4Read the IMS status with *#*#4636#*#*This is the most precise check because it shows whether the phone actually registered with the carrier's network. Details are in the next section.

How do you read IMS status with *#*#4636#*#*?

Open the Phone app and type *#*#4636#*#* without pressing call. A testing screen opens by itself. Choose Phone information, tap the three-dot menu in the top-right corner and pick IMS Service Status. The screen shows IMS Registration as Registered or Not Registered, and lists Voice over LTE and Voice over WiFi separately as Available or Unavailable.

The *#*#4636#*#* screen is an Android test menu, not a consumer settings page. Only read it. Do not change values such as the preferred network type there, because the phone may then latch onto the wrong network until you restart it.

Where is the Wi-Fi Calling setting on each Android brand?

Menu names differ by brand, by OS version and sometimes by the carrier of the inserted SIM. This table collects the paths that makers or carriers document for Android 14–16. If your phone's labels do not match, use the search box in Settings.

Turning on Wi-Fi Calling on a Pixel, step by step

1. 1Connect to Wi-Fi firstMake sure the phone has working internet over Wi-Fi; load a web page to confirm.
2. 2Open the SIM menuSettings > Network & internet > SIMs, then tap your carrier's SIM.
3. 3Turn on Wi-Fi callingScroll to Wi-Fi calling and switch it on. Google says that if you cannot find this option, your carrier does not support the feature.
4. 4Look for the confirmationOnce ready, Wi-Fi calling or Internet call appears on the notification screen or during a call.

Samsung has its own One UI details, such as the Quick settings tile and per-SIM options, which we cover in a separate guide.

Detailed Wi-Fi Calling setup on Samsung Galaxy

Do you need to register with your carrier first? AIS, True, dtac and NT

On some Android phones the carrier has to enable the service before the switch on the phone does anything. Here is what each Thai carrier's official page says.

• AIS: register by dialling *399*1#, or through m.ais.co.th/ApplyAISVoWiFi, after checking your model at ais.th/4g/vowifi. Then turn on the switch on the phone.
• True and dtac: the True-dtac guide says Settings > Connections > Wi-Fi Calling, pick the number, then choose WiFi Preferred. The feature must be switched on while you are still in Thailand, and restarting the phone once is the first fix if it misbehaves.
• NT Mobile: dial *834# to switch VoLTE, Wi-Fi Calling or both on or off. It works for prepaid and postpaid, outgoing calls are billed at normal package rates, and incoming calls are free.

On cost, Wi-Fi Calling generally uses minutes from your normal voice package; it is not free calling. For package-specific terms at AIS, True and dtac, check the carrier's official page or call them, because conditions differ by package.

AIS Wi-Fi Calling setup in detail

Should you choose Wi-Fi preferred or mobile preferred?

The calling preference tells the phone which route to use first when both Wi-Fi and a cell signal are available. Some phones show two options, some three, and some carriers hide the choice entirely.

For most Thai users, Wi-Fi preferred is the right choice, and it is what the True-dtac and NT guides specify. The places where you need Wi-Fi Calling are rooms the signal does not reach. With mobile preferred, the phone may cling to a one-bar signal and never move to Wi-Fi, so calls still drop. Abroad, this setting matters less than Airplane Mode, because Airplane Mode removes the cell network from the choice altogether.

After turning it on, how do you confirm Wi-Fi Calling really works?

A switch that is on does not prove anything. Test at home before you travel; it takes under five minutes.

1. 1Turn on Airplane Mode, then turn Wi-Fi back onThis cuts the cell radio and leaves only Wi-Fi, so you know for sure the call is not using a tower.
2. 2Wait for the iconGive it 30 seconds to a minute until a phone-with-Wi-Fi icon appears in the status bar, or the carrier name shows Wi-Fi. On AIS, look for the AIS WiFi Call label.
3. 3Call out, then have someone call you backCall someone you know, then ask them to call your number back. If both directions connect, outgoing and incoming calls work over Wi-Fi.
4. 4Test an SMSAsk them to send you one SMS. Many carriers deliver SMS over the same IMS system, but not every carrier or phone does, so try it before you rely on OTP codes on a trip.
5. 5If it fails, read the IMS screenDial *#*#4636#*#*, check whether Voice over WiFi says Available, and compare with the table above.

Can you use Wi-Fi Calling on Android while abroad?

In many cases, yes. Wi-Fi Calling lets your Thai number make and receive calls over hotel or café Wi-Fi. Both AIS and True-dtac tell travellers to turn on Airplane Mode, turn Wi-Fi back on and check the icon before dialling, so the call does not go out over normal voice roaming, which is billed at roaming rates.

• Some public Wi-Fi blocks VPN/IPsec traffic, so Wi-Fi Calling never registers. True-dtac suggests trying another Wi-Fi or a shared hotspot.
• Hotel Wi-Fi with a login page has to be signed into before Wi-Fi Calling can register.
• Some countries restrict internet calling, and some foreign carriers restrict their own customers' VoWiFi while roaming. No official country list exists for Thai carriers, so always keep a backup plan.

Can the data from a travel eSIM replace Wi-Fi?

Most travel eSIMs, including esimonline's, are data-only with no phone number, so Wi-Fi Calling always belongs to your Thai number. The question is whether the Thai line can ride on the other SIM's mobile data inside the same phone instead of Wi-Fi. On Android, the answer is: only on some models, with no guarantee.

• Google Pixel 8a and later: Google's help page says using both SIMs this way requires mobile data on for both SIMs, automatic data switching on for the second SIM, and Wi-Fi calling support from the second SIM's carrier. Google does not say whether it works while the home SIM is roaming.
• Samsung: some non-US models have a feature users call Backup calling, but we found no official Samsung page describing its conditions, and users report it tends to work only when the data SIM is not roaming.
• Other brands: Pantip users report mixed results by carrier, for example AIS working and True not, but these are user reports, not carrier statements.

If you try it, keep data roaming off on the Thai SIM, set the travel eSIM as the main data SIM, and check that the Wi-Fi Calling icon appears before you dial. If it does not, go back to Wi-Fi, which is the route carriers officially support.

How your phone number and a data-only eSIM work together

What if the Wi-Fi Calling menu is missing or does not work?

1. Update and restart: carrier configuration often arrives with system updates, and True-dtac lists restarting once as the first fix.
2. Check you picked the right SIM: on dual-SIM phones the switch is per SIM, so turn it on for your Thai number, not for the travel eSIM.
3. Turn on VoLTE too: many carriers need VoLTE enabled before Wi-Fi Calling will work.
4. Change Wi-Fi: try a hotspot from another phone. If that works, the original Wi-Fi is blocking UDP ports 500/4500.
5. Turn off VPN: an always-on VPN can stop the tunnel to the ePDG from forming.
6. Grey-import or other-region firmware: software not built for Thai carriers may have no menu at all; ask the service centre or the carrier whether that model is supported.
7. Call the carrier: AIS 1175, True 1242, dtac 1678, NT 1888, and ask them to confirm VoWiFi is provisioned on your number.

Full fixes for a missing Wi-Fi Calling menu

Frequently asked questions about Wi-Fi Calling on Android