AIS Wi-Fi Calling: how to activate it, set up your phone, check support and use it

What is AIS Wi-Fi Calling and which SIMs can use it?

AIS Wi-Fi Calling is AIS's service for making and receiving calls on your own AIS number over any Wi-Fi network, in Thailand or anywhere in the world. You activate it by registering with *399*1# and then switching Wi-Fi Calling on in a supported phone.

AIS markets the service as AIS Wi-Fi Calling, and its web page also uses the name AIS 4G VoWiFi (Voice over Wi-Fi). Technically it is standard 3GPP VoWiFi: the phone builds an encrypted IPsec tunnel over the internet to an AIS network element called the ePDG, then registers with the same IMS core that carries VoLTE calls. The person you call sees your normal AIS number, you do not install an app, and the other side does not need Wi-Fi Calling. That is the key difference from LINE or WhatsApp calls, where both sides need the same app.

Who can use it: the AIS service page covers both postpaid and prepaid customers, with one important condition. Under rules set by the NBTC (Thailand's telecom regulator), prepaid customers using VoWiFi must verify their identity with their national ID card at an AIS Shop, Telewiz or Buddy Exclusive branch. Existing prepaid users had a deadline of 31 March 2025, after which AIS reserved the right to suspend VoWiFi, and new customers must register and verify before they can use it. The AIS FAQ also states that if a number has never been identity-verified at a branch, it cannot self-register for Wi-Fi Calling, whether it is postpaid or prepaid.

• It works on an AIS physical SIM or eSIM that carries the number. If you use the AIS Multi SIM service, Wi-Fi Calling works on the main SIM only.
• Registering for Wi-Fi Calling automatically turns on AIS HD Voice (4G VoLTE) as well. The reverse is not true: having only HD Voice does not give you Wi-Fi Calling.
• If you switch from prepaid to postpaid, Wi-Fi Calling carries over and you do not need to register again.
• Any Wi-Fi works, including AIS Fibre, True, 3BB, home broadband and public hotspots, unless that network blocks internet calling (VoIP).

The basics: what Wi-Fi Calling is and how it works

Which phones support AIS Wi-Fi Calling, and how do you check?

AIS keeps its supported-device list on the AIS Wi-Fi Calling page (ais.th, under postpaid > services > vowifi), with tabs for Apple, Samsung, Vivo, Oppo, Xiaomi and Other. The AIS Call Center articles also point to ais.th/4g/vowifi and tell you to check your model before registering. The reason is that Wi-Fi Calling does not depend on hardware alone: the phone also needs carrier configuration for AIS with the feature switched on.

Software conditions from AIS: an iPhone needs iOS 9.3 or later with the latest carrier bundle, and an Android phone needs the latest firmware that supports Wi-Fi Calling. For a quick self-check, insert the AIS SIM and see whether a Wi-Fi Calling option appears in Settings. On an iPhone you can see the carrier settings version under Settings > General > About > Carrier.

Phones that support Wi-Fi Calling, and how to check yours

How do you register for AIS Wi-Fi Calling, and does it work straight away?

Unlike simply flipping a switch, AIS asks you to register the service on the network side first. The steps from the AIS page are:

1. 1Check the model and update the phoneConfirm your model is on the AIS Wi-Fi Calling list, then update iOS and the carrier bundle, or the Android firmware, to the latest version.
2. 2Verify your identity if you have not alreadyEspecially for prepaid numbers, take your national ID card and SIM to an AIS Shop, Telewiz or Buddy Exclusive branch to verify. If you skip this, self-registration usually fails.
3. 3Dial *399*1# and press callOr register on the web at m.ais.co.th/ApplyAISVoWiFi from the phone using that AIS number.
4. 4Wait up to 24 hoursAIS says the service becomes usable within 24 hours of registering, so it may not work immediately.
5. 5Turn it on in the phone and look for the iconSwitch it on as described in the next section, join a Wi-Fi network with working internet, and wait for the AIS WiFi Call label (iPhone) or the phone-with-Wi-Fi icon (Android) before you call.

Finish registration while you are still in Thailand. Several Pantip threads describe people trying to register from abroad and getting stuck: the code gets no response, or the iPhone reports that the account is not authorised and to contact AIS. A common cause is missing identity verification, and that has to be done at a branch in Thailand.

Where do you turn on AIS Wi-Fi Calling on iPhone and Android?

iPhone

1. 1Open Settings > CellularIf the phone has two SIMs, tap the AIS line first, because Wi-Fi Calling is set per line.
2. 2Tap Wi-Fi CallingTurn on Wi-Fi Calling on This iPhone and tap Enable. The phone may ask you to confirm an address for emergency services.
3. 3Wait for it to activateWhen it is ready you will see AIS WiFi Call in the status bar or in Control Center.

The AIS page shows two paths. Its current step-by-step uses Settings > Cellular > Wi-Fi Calling, which matches Apple's own support article. The older AIS FAQ still says Settings > Phone > Wi-Fi Calling on This iPhone, which is the menu from older iOS versions. If you cannot find it on iOS 18 or iOS 26, pull down on the Settings screen and search for Wi-Fi Calling. Menu names in Thai can differ slightly between versions.

Samsung and other Android phones

• Samsung (One UI 6 to 8): Settings > Connections > Wi-Fi Calling and switch it on, or go through the Phone app > three dots > Settings > Wi-Fi calling.
• Other Android phones (Android 14 to 16, such as Xiaomi, Oppo, Vivo and Pixel): usually Settings > SIM cards & mobile networks (or Network & internet > SIMs) > choose the AIS SIM > Wi-Fi calling. Names vary by brand and model.
• Preference: in Thailand the default is Mobile Network Preferred, and the phone switches to Wi-Fi Calling on its own when the cellular signal is weak. Choose Wi-Fi Preferred if you want Wi-Fi first. AIS tells Android users to set Wi-Fi Preferred when abroad.
• Icon to look for: on Android it is a phone handset with Wi-Fi waves in the status bar.

An iPhone has no preference setting like Android. Once Wi-Fi Calling on This iPhone is on, in Thailand the phone decides by itself whether to use cellular or Wi-Fi (AIS notes you cannot choose), and abroad it uses Wi-Fi first whenever Wi-Fi is available.

Detailed iPhone setup guide

Does AIS Wi-Fi Calling cost money, and how is it billed?

AIS does not list a separate registration fee, but calls are not free. Outgoing calls are billed against your current domestic package and incoming calls are not charged, so the real per-minute cost depends on your own plan. You can check remaining minutes in myAIS > Package > My package > View details.

The AIS page carries a footnote saying the special rate for outgoing and incoming calls abroad ends on 30 September 2026 (2569 in the Thai calendar). Rates abroad may change after that date, so if you are travelling around now, open the current AIS Wi-Fi Calling page or call 1175 before you leave rather than assuming your last trip's pricing still applies.

Two cases catch people out. First, on Home Zone plans with cheap calls inside one region, the system treats Wi-Fi Calling as calls made from Bangkok. The AIS FAQ example is a northern-region SIM: a Wi-Fi call made in Chiang Mai is billed as an out-of-zone call. Second, Serenade customers with free roaming calls to the Call Center do not get that benefit over Wi-Fi Calling; a call to 1175 over Wi-Fi Calling is billed against the domestic package instead.

Does Wi-Fi Calling cost money? All carriers compared

How do you use AIS Wi-Fi Calling abroad without paying roaming rates?

AIS's rule comes down to one thing: only call or answer when the Wi-Fi Calling icon is showing. AIS states plainly that it is not responsible for international charges caused by the phone connecting to a local operator's network in that country. The steps AIS recommends are:

1. Register and test Wi-Fi Calling while you are still in Thailand.
2. On arrival, keep Airplane Mode on the whole time so the phone cannot use voice roaming.
3. Turn Wi-Fi back on by itself and join a network that actually reaches the internet (at a hotel, finish the login page first).
4. Android: set Wi-Fi Preferred. iPhone: check that Wi-Fi Calling on This iPhone is still on.
5. Wait for AIS WiFi Call or the Wi-Fi phone icon before calling. Thai numbers can be dialled as normal, with no +66.

Limits abroad, as AIS describes them: Wi-Fi Calling may not work if the Wi-Fi provider blocks it, or in countries whose law does not allow internet (VoIP) calling, and AIS names China as an example. To reach a foreign special number, such as a local emergency number, you have to turn Wi-Fi off and call over the cellular network on roaming, which is billed at international roaming rates.

Using Wi-Fi Calling abroad: the full guide

Can you use AIS Wi-Fi Calling together with a travel eSIM?

Most travel eSIMs, including esimonline's, are data-only and come with no phone number. If you want people to keep reaching your AIS number, Wi-Fi Calling has to run on your own AIS line, not on the travel eSIM. The real question is where the AIS line gets its internet connection from.

• The route AIS confirms: hotel or café Wi-Fi, or a hotspot from another device. The AIS FAQ says one device can share a Wi-Fi hotspot to another device that uses Wi-Fi Calling, with no brand or model restriction, as long as the Wi-Fi Calling phone does not slip onto voice roaming. For example, put the travel eSIM in a tablet or second phone and share its data.
• One phone with two SIMs (AIS plus a travel eSIM): the AIS page does not cover running AIS Wi-Fi Calling over another SIM's mobile data, and its Airplane Mode advice would switch the eSIM off too. Some phones have a feature that lets one SIM borrow the other SIM's data for calls, but it depends on brand, model and carrier, so we cannot confirm it works with AIS. If you try it, turn roaming off on the AIS line and check that AIS WiFi Call appears before every call.
• OTP and SMS: while Wi-Fi Calling is connected, SMS to your AIS number arrives as normal, and sending is billed against the domestic package.

Browse data-only travel eSIMs

AIS Wi-Fi Calling not working or not showing: how do you fix it?

Work through these in order, from the most common cause down:

1. Not registered yet, or less than 24 hours since registering: dial *399*1# again, or ask 1175 whether the service is active on your number.
2. Identity not verified at a branch: the main cause for prepaid numbers. Visit a branch with your ID card.
3. The phone is not on the list or is an import: the Wi-Fi Calling menu may not appear at all because the firmware has no AIS profile.
4. Old iOS, carrier bundle or firmware: update everything, then restart the phone.
5. Wi-Fi connected but no internet: AIS says Wi-Fi Calling cannot work in this case. Open a web page to test, and on public Wi-Fi complete the login page first.
6. The Wi-Fi blocks VoIP or ports: VoWiFi needs UDP ports 500 and 4500 open to the ePDG. If a company or hotel network blocks them, try another network or a hotspot.
7. Call Screening is on: per the AIS FAQ, Call Screening has to be cancelled before Wi-Fi Calling will work.
8. Still stuck: switch Wi-Fi Calling off and on, reset network settings, then call 1175 and ask them to check the service status on your number.

Limits that are not faults: Miss Call Alert does not work while you use Wi-Fi Calling. Video calls over Wi-Fi Calling cannot do conferences or call forwarding, and if the other side cannot take video, the call switches to voice without warning. Short numbers that need your location, such as 191 and 1669, may not connect over Wi-Fi Calling, so in a real emergency call over the cellular network. Turning mobile internet off with *129*1# does not affect Wi-Fi Calling.

Wi-Fi Calling not working: full troubleshooting

How do you cancel AIS Wi-Fi Calling or contact AIS on 1175?

To cancel the service, dial *399*2# and press call. If you only want the phone to stop using Wi-Fi Calling for a while, switch it off in Settings instead of cancelling, because registering again from abroad can run into the problems described above.

The AIS Call Center number is 1175. The AIS page lists 1175 among the numbers you can call over Wi-Fi Calling, billed at the domestic rate or package even when you are abroad, so it is cheaper than calling over roaming. You can see your Wi-Fi Calling usage in the myAIS app. Before calling, note your phone model, iOS or Android version and any error message you saw.