New ARC Number Not Accepted? Which Apps and Websites Work in Taiwan (2026)

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New ARC number not accepted by an app or website in Taiwan? See which banks, payment apps, government sites and tickets work in 2026, and what to do next.

If you have ever typed your resident number into a Taiwanese app and got a red "格式錯誤" (format error), you are not alone: "new ARC number not accepted" is one of the most common complaints among foreign residents, and it still happens in 2026. The good news is that far more things work now than five years ago. The bad news is that the failures are unpredictable, so you need to know which services are safe, which are hit and miss, and what to do when you get stuck.

Official NIA sample of a Taiwan Resident Certificate showing a new-format UI number A900000016

Photo: Wikimedia Commons, public domain (National Immigration Agency sample card)

Old vs new ARC number: what actually changed

Your ARC carries a Unified ID number (統一證號, often called the UI number). Until the end of 2020 it was 2 letters plus 8 digits, for example AC01234567. Taiwanese national IDs are 1 letter plus 9 digits, and thousands of websites were built to check only that pattern, so foreigners were locked out of online shopping, ticket booking and banking.

On 2 January 2021 the National Immigration Agency (NIA) switched to a new format that copies the national ID: 1 letter plus 9 digits. The only difference is the second character. Citizens have 1 (male) or 2 (female); foreign residents get 8 (male) or 9 (female). Look at the sample card above: A900000016.

Key dates, from the NIA's own notice:

The same number system covers APRC holders and the TARC (臺灣地區居留證) issued to nationals without household registration, which matters later.

Why some systems still reject the new format

The new format fixed the "wrong pattern" problem, but it exposed a second one. Many apps do not just check the pattern, they verify your number against the household registration database, which foreigners are not in. So the form accepts your number and then says it cannot verify you. Others check that the second digit is 1 or 2, a one-line fix nobody has made. And some companies simply decided not to serve foreigners: E.Sun told a complaining customer in 2024 that supporting foreigners in its wallet app was too much work, and in January 2026 its new MRT QR payment feature still said only national ID holders may register.

A quieter problem: your telecom or bank may have registered your passport number as your ID. Then any service that cross-checks with them (paying a phone bill through LINE, logging in with mobile phone authentication) fails even though your ARC number is fine.

Status table: what works in 2026

This is compiled from the long-running Forumosa testing and reporting thread (over 1,000 replies since 2021), the community identity.tw transparency report, and official FAQs. Dates are the latest report we found. Things change, so treat old dates with suspicion.

A 24-hour ATM area at a Taiwan Cooperative Bank branch in Ximen, Taipei

Photo: Solomon203 via Wikimedia Commons, CC BY-SA 4.0

The 2026 twist: TARC holders have the same problem

People who naturalize as Taiwanese first receive a TARC while they wait for household registration. In late August 2026 Forumosa users started a separate thread because the TARC uses exactly the same 8/9 number, so new citizens hit the same walls. Reported cases include the Tourism Administration's weekday lodging subsidy, the Ministry of Sports' "揮汗有禮" exercise rewards (1 September to 30 November 2026), and a bank branch that told a new citizen updating his card would cancel his credit card. Government replies said the systems verify against household registration, and changes would be "considered for future programs." Our take: if the government will not fix this for its own nationals, do not expect subsidy sites to open to ARC holders soon.

Should you switch if you still have an old number?

Yes, at your next renewal. It is free when combined with a renewal, the old number dies on 1 January 2031, and some sites now go the other way: Cathay's insurance website asks policyholders to update to the new format. The cost is an afternoon of updating your bank, telecom, insurer and broker. Do it in one batch, not over months, and bring the new card plus your passport to each branch.

New ARC number not accepted? What to do when a site rejects you

1. If you have an old number on the back of your card, try it. Some older systems only know that one.

2. Look for a hidden "外籍人士", "居留證" or "護照" (passport) option, often a small tab or dropdown. Use the passport route for tickets.

3. Check the name field. Use capitals and the exact spacing on your ARC; this fixed the LINE Pay problem.

4. Call customer service. The phrases below are listed after these steps.

5. Complain, and complain to the right place. For a government site, use the agency's director mailbox; the NIA's is bossmail.immigration.gov.tw. For banks and insurers, complain to the company first, then the Financial Ombudsman Institution if it stalls. For Taipei city services, call 1999. For general help in English, the NIA foreign residents hotline is 0800-024-111. Forumosa reports show complaints do get things fixed: the New Taipei traffic video platform and the tax payment site both changed after users wrote in.

Phrases for customer service calls

Commuters on a Taipei MRT platform at Zhongxiao Fuxing station, many looking at smartphones

Photo: Hauskyg YWICAORP via Wikimedia Commons, CC0

Our practical picks

For the bank side in more depth, see our guides on which bank to choose and opening an account and phone plan. If you are moving soon, remember that an address change is a natural moment to switch numbers too: see updating your ARC address.

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