If you have replaced a transit card, the number registered in Korea's Modu Card service may no longer match the card you actually use. In an October 20, 2026 announcement, the Ministry of Land, Infrastructure and Transport's Metropolitan Transport Commission asked people with a mismatch to update the registration by October 26. That is narrower than telling every member to replace or re-register a card. The ministry's two-page press-release PDF spells out both the deadline and the separate maintenance window.

Who needs to change anything?

First, compare the number registered in your Modu Card account with the number on the card currently being used. If they match, the ministry says no change is needed. If they differ—for example, after a replacement—log in to the official website or app and change the registration to the number of the card in use. The commission warned that a continued mismatch could disrupt transit-fare refunds for travel from October 27 onward. It did not say that every rider's balance or accrued refund automatically disappears that day.

Two blank cards beside a face-down phone; not an actual service registration or account.

Use the official Modu Card site or its app for your own comparison. Do not send your card number or login details to an unknown person who offers to “check” them. After correcting a mismatch, look at the saved number again. The public notice describes a general process; it cannot confirm the status of your individual account.

Does the service stop working on October 27?

The ministry says registration changes can be made until midnight at the end of October 26. Rather than rely on the last minutes, check and correct a mismatch earlier that day. This is a deadline to bring account information into line, not a requirement to obtain a new physical card.

From 12:00 a.m. to 10:00 a.m. on October 27, system improvements and maintenance prevent new member registration and card registration or changes. The finishing time may vary. The same notice explicitly says people can continue using public transport during maintenance and that transit-refund credits continue to accrue normally. A possible refund problem caused by a mismatched registered card number is different from maintenance of the registration functions. Official PDF, p. 2.

A generic bus commute with an unmarked card; not evidence of a particular fare or refund.

A short check before the deadline

  1. Find the number of the card you currently use.
  2. Compare it with the number registered in the official service.
  3. If they are the same, leave it unchanged. If different, replace the registered number with the current one.
  4. Verify the saved number and consult the official site for any updated maintenance notice.

This guide does not access members' accounts or predict a person's exact refund outcome.

About the Author

Life Mokcha compared the Metropolitan Transport Commission's October 20 release and its attached PDF. It did not inspect any reader's card, account or refund record.

The original Life Mokcha post on Naver is also available in Korean.

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