Does Your Taiwanese Carrier's Wi-Fi Calling Work Abroad? Chunghwa Telecom, Taiwan Mobile, FarEasTone, T Star (2026)

Wi-Fi Calling is the feature that makes the “keep my Taiwan mobile number reachable abroad” trick work. Your number rings and receives SMS over hotel, apartment, hostel, café or friend’s Wi-Fi instead of expensive international roaming. The catch: each carrier words its overseas policy slightly differently, and post-merger sub-brand messaging can lag behind the actual network. Since terms change, treat the notes below as “what to check,” not a guarantee, and always confirm on your carrier’s own support page.

International roaming vs Wi-Fi Calling — the money question

Chunghwa, Taiwan Mobile and FarEasTone each sell international roaming (per-day and per-trip) with regionally priced tiers — Japan/Korea/HK are usually cheaper than Europe or the US. Even so, a couple of weeks in Europe on a daily pack adds up. The reliable, cost-predictable approach for any plan is the same: keep your Taiwan mobile number reachable over Wi-Fi Calling for calls and SMS (so your bank OTPs land), and carry your data on a travel eSIM. Your bank codes, TW FidO SMS, LINE calls and family calls all still land on your normal Taiwan number, while your data bill is a flat prepaid number you chose before leaving.

The three things to verify for any carrier

1. Is Wi-Fi Calling allowed from outside Taiwan on your plan and handset? Most say yes on modern iPhones and certified Android handsets; some legacy prepaid tariffs restrict it. This is the single most important line in the fine print.
2. How are calls/SMS over Wi-Fi billed abroad? On most post-paid plans, Wi-Fi calls and SMS to Taiwanese numbers are treated as domestic (i.e. included). Calls to local foreign numbers may differ.
3. Does the plan keep the number active if you barely use it? Critical for long stays and overseas students — post-paid holds the number as long as you keep paying; prepaid needs periodic activity or a top-up.

Carrier-by-carrier — what to check

Chunghwa Telecom (中華電信)

Chunghwa Telecom is the largest and historically most conservative operator. Wi-Fi Calling is supported on many post-paid plans and on most modern iPhones and eligible Android handsets. Confirm whether your specific plan permits it overseas, whether your Android device is on Chunghwa’s Wi-Fi Calling supported list, and how Chunghwa bills Wi-Fi calls to Taiwanese vs foreign numbers on Chunghwa Telecom’s official Wi-Fi Calling support page. Turn international roaming off if you plan to rely purely on Wi-Fi Calling plus an eSIM.

Taiwan Mobile (台灣大哥大) — includes former T Star / Taiwan Star (台灣之星)

Taiwan Mobile supports Wi-Fi Calling across much of its post-paid lineup. Former Taiwan Star (台灣之星) customers were migrated onto Taiwan Mobile’s network in 2023 and generally follow Taiwan Mobile’s Wi-Fi Calling rules on supported handsets — but sub-brand help pages sometimes lag, so read the current article for your exact plan. Make sure VoLTE is enabled on the handset, or Wi-Fi Calling may not turn on.

FarEasTone (遠傳電信) — includes former Asia Pacific Telecom (亞太電信)

FarEasTone supports Wi-Fi Calling on compatible devices and plans. Former Asia Pacific Telecom (亞太電信) customers were migrated onto FarEasTone’s network in 2023–2024. Check whether your plan permits Wi-Fi Calling internationally, whether your handset is on FarEasTone’s supported list, and how Wi-Fi SMS/calls to Taiwanese vs local numbers are charged. Confirm VoLTE is on and the emergency address is set before you fly.

Long-stay and expat picks — the cheapest ways to keep a Taiwan number

For studying / working overseas long-term while keeping a Taiwan number, cheap post-paid plans on Chunghwa, Taiwan Mobile or FarEasTone are the sweet spot — an active plan is the safest way to hold the number and keep Wi-Fi Calling switched on. If you’re on prepaid, keep an eye on the expiry / top-up window so the number doesn’t lapse. Send yourself the occasional SMS to stay current.

A note on honesty: why we don’t print exact prices here

Carrier plans, international roaming pricing, post-merger sub-brand rules and Wi-Fi Calling supported- handset lists change often enough that a hard-coded table would be wrong within months — and being wrong about whether your Cathay United OTP will reach you at a Tokyo hotel is the kind of mistake that strands you. So the reliable move is always the same: open your carrier’s official Wi-Fi Calling support page, search “Wi-Fi Calling 海外” or “overseas,” and read the line about international use for your exact plan and handset. Then test it at home before you fly.

Test Wi-Fi Calling before you leave Taiwan

1. Turn on Wi-Fi Calling for your Taiwanese line and confirm VoLTE is on.
2. Enter the emergency address if your carrier asks for one — you may not be able to set it abroad.
3. Simulate “abroad”: enable Airplane Mode (飛航模式), then turn Wi-Fi back on. Your phone now has only Wi-Fi, like a hotel room in Tokyo, Seoul, Hong Kong or Bangkok.
4. Call yourself from another phone and send yourself an SMS. Both should connect over Wi-Fi.
5. Request an OTP from Cathay United, E.SUN, CTBC, Fubon or Mega, and trigger a TW FidO / MyData login — confirm the SMS lands.

If all four work at home on Wi-Fi-only, they’ll work the same way in a hotel in Tokyo, a hostel in Seoul, or an Airbnb in Bangkok.

Wi-Fi Calling handles your number. The eSIM handles your data.

Wi-Fi Calling does not give you data, and it only works when you’re on Wi-Fi. The moment you’re walking around — Google Maps, LINE, Naver Map, Uber, Grab, translation — you need real mobile data. That’s the travel eSIM’s job, and it sidesteps international roaming entirely. Keep data roaming off on your Taiwanese line and on for the eSIM, set the eSIM as your data line, and turn off automatic data switching so your Taiwan carrier can never grab foreign data behind your back. Full toggle walkthrough in our Wi-Fi Calling + eSIM setup guide.

FAQ

Bottom line

Whatever your carrier — Chunghwa Telecom, Taiwan Mobile, FarEasTone or T Star — the playbook is the same: confirm Wi-Fi Calling works abroad on your plan and handset, skip the daily international roaming pack, test at home, and let a travel eSIM carry your data. See the full Keep Your Phone Number Abroad guide, grab data for Japan, South Korea, Hong Kong, Thailand or anywhere else, and browse by destination.

Related guides

• Keep Your Phone Number Abroad — Complete Guide
• Keep 2FA & verification codes working while travelling — the country list of where Wi-Fi Calling is blocked or unreliable
• Hong Kong carriers — same guide for +852 numbers
• Wi-Fi Calling + eSIM setup guide
• Data Roaming ON or OFF?
• iPhone Dual SIM Setup for Travel