Getting a SIM Card in Taiwan: Prepaid vs Contract, and the Two-ID Rule

The lay of the land

Taiwan’s mobile market is dominated by three major carriers — Chunghwa Telecom, Taiwan Mobile and Far EasTone — plus budget sub-brands and MVNOs riding their networks. Coverage from the big three is excellent island-wide, including the metro systems and most mountain routes; the practical difference between them for a newcomer is small.

The two-document rule is the thing to know. Taiwanese regulation requires foreigners registering a SIM to present two forms of identification — in practice a passport plus one more document (ARC if you have one; otherwise a second photo ID such as a driver’s licence from home, or an entry-stamp-bearing document, depending on the carrier’s current policy).

This applies even to prepaid tourist SIMs, which is why the airport counter asks for your passport and something else. Bring a second ID to any SIM transaction and the process is smooth.

Where to buy

• Airport counters (Taoyuan, Songshan, Kaohsiung) — carrier booths sell tourist/prepaid SIMs on the spot; this is the easiest first stop
• Carrier retail stores in every town — same products, sometimes more plan options, English proficiency varies by branch
• eSIM — the major carriers offer eSIM provisioning for supported phones on many plans; travel eSIM resellers also cover Taiwan, though a local number (see below) is worth having over a data-only eSIM if you are staying

As of August 2026. Registration rules and plan structures change — carrier sites and the NCC (telecom regulator) are the reference points.

Prepaid first: the arrival play

For anyone arriving to live in Taiwan, the sensible sequence is prepaid on day one, contract later (or never).

Prepaid SIMs

• Sold in fixed-day packages (e.g. 30-day) with unlimited or large data allowances, and as top-up plans for longer use
• Registered on the spot with passport + second ID
• Include a real Taiwanese phone number — not just data — which matters for everything in the next section
• Renewable/top-uppable online or at convenience stores; a prepaid number can be kept alive long term

Why not just use roaming or a travel eSIM? Both work for data, but neither gives you a usable local number, and Taiwan is a place where the local number is infrastructure: banks send OTPs to it, delivery drivers call it, restaurants take bookings on it, and government e-services verify against it. A data-only solution starts costing you time within the first week of actual residence.

Practical notes

• Top-ups at convenience stores (7-Eleven, FamilyMart) are trivial — the clerk does it in a minute
• Keep the little card with your number/PUK details; carrier stores will ask for ID for any account change
• Speeds and deprioritisation on unlimited plans vary by price tier; the cheapest unlimited tiers are throttled after thresholds on some carriers — read the plan sheet

Postpaid contracts: when and why

Postpaid effectively requires an ARC. Carriers want the residence document plus, in some cases, a deposit or a local guarantor for newer arrivals. With an ARC in hand, signing a contract is routine.

Why bother converting from prepaid?

• Monthly cost for heavy data is usually lower on contract promotions
• Handset bundles — if you want a phone on instalments, contract is the route
• Family/duo discounts and home-internet bundles

Why many foreigners never convert: long contract terms with early-termination fees sit badly with visa-length uncertainty. If your ARC runs one year at a time, a 30-month handset contract is a mismatch — and terminating early because you left the country is exactly the fee trap it sounds like. Prepaid or no-contract monthly plans avoid the whole problem.

If you do sign a contract

• Bring ARC + passport (two-ID rule again) and your chop or signature
• Check the contract length and the early-termination formula before anything else
• Number portability exists — you can keep your prepaid number when converting to postpaid, at the same or a different carrier. Ask for it explicitly; it preserves every service tied to your number
• Confirm the app/billing interface has English if you need it — coverage is inconsistent across carriers

Your number as identity — treat it accordingly

In Taiwan your mobile number quietly becomes an identity credential:

• Banking OTPs go to it — change numbers carelessly and you lock yourself out of your own bank app
• Government portals and NHI services use it for verification steps
• E-commerce and delivery — Shopee, food delivery and convenience-store pickup all run on the number
• Mobile payment registration references it

Three habits that prevent real pain later:

1. Pick a number you will keep, and use number portability rather than abandoning it when switching carriers or converting prepaid → postpaid
2. Keep the SIM registered in your own name with your current documents — an ARC renewal or passport change should be reflected at the carrier, or account-service requests can stall at the ID check
3. Before leaving Taiwan for good, unbind the number from bank and government accounts first, then cancel the line. Cancelling first and discovering your bank still texts the dead number is a common and painful ordering mistake

Troubleshooting quick hits

• SMS not arriving from banks: often a carrier-level spam filter or a number recorded with an old format — the branch/carrier can check which side is failing
• Lost SIM: carriers reissue against your ID at any retail store; do it fast, since the number is your OTP channel
• Poor signal indoors: all three carriers offer WiFi-calling on supported handsets — enable it rather than switching carriers over one bad building