Buying and loading a T-money card does not, by itself, register your child’s fare discount. Have the child’s birth date registered before relying on the lower fare. For Seoul’s ordinary subway card base fare, the published difference is ₩550 for a child versus ₩1,550 for an adult. A card handed down from someone else needs an additional check: changing its registered birth date can take three working days to affect the fare.
These figures and registration steps were checked October 23, 2026, against Seoul’s subway fare table and Tmoney’s current registration guide. This guide covers physical T-money cards for family trips.
Match the child’s age to the fare category
Tmoney’s English visitor guide defines children as ages 6–12 and youth as ages 13–18. It says to present the card and identification when registering the birth date at a convenience store or subway information center.
| Passenger category | Ordinary Seoul subway card base fare |
|---|---|
| Adult | ₩1,550 |
| Youth, ages 13–18 | ₩900 |
| Child, ages 6–12 | ₩550 |
Scope: these are the current amounts in Seoul’s table effective June 28, 2025, not a nationwide price for every bus or train. Distance, route and other fare conditions can change the total. For a child under six, check the operator’s free-accompaniment and seat rules rather than selecting a category from this table. Intercity trains have separate rules; see our KTX infant and child-seat fare guide.
Ask for registration when buying the card
The Korea Tourism Organization’s card guide tells young visitors to register their date of birth when purchasing a card. Make that a separate request from adding money to the balance.
Have the physical card and age identification ready. For an overseas child, carry their passport. You can show staff this request:
아이 생년월일을 등록해서 어린이 할인을 적용해 주세요.
Please register my child’s date of birth for the child discount.
For a teenager, replace 어린이 할인 with 청소년 할인. Ask staff to confirm that the birth date was recorded, then label the card so the right family member keeps using it.
Tmoney’s registration instructions distinguish three routes:
| Card or purchase route | Registration step |
|---|---|
| All-age card at GS25, CU, 7-Eleven, Emart24 or a listed subway customer center | Birth-date registration at purchase completes the process. |
| All-age card from another seller | Set the child/youth fare type, then register the birth date within 10 days of first use. |
| Designated child/youth card | Register the birth date online within 10 days of first use. |
Missing required registration means ordinary fares. Do not interpret the deadline as ten automatic days of discounted travel.
Online registration has a non-member child/youth option requiring the card number and birth date. Follow through to the confirmation.
A borrowed card has a different timing problem
For a handed-down card, update the birth date online, at a convenience store or a listed subway center. Tmoney specifies three working days before the corrected discount applies.
For a short holiday, compare a new card’s purchase cost with the extra fares during that wait. Confirm timing with staff before choosing either option.
What the difference means for a family budget
Here is a calculated example, not a ticket quote: two adults and two eligible children each make four separate journeys charged at the ordinary Seoul subway base fare above.
| Calculation | Total |
|---|---|
| Two adults × four journeys × ₩1,550 | ₩12,400 |
| Two children × four journeys × ₩550 | ₩4,400 |
| Family total with the child fares | ₩16,800 |
| Same 16 passenger journeys all charged at ₩1,550 | ₩24,800 |
| Difference in this example | ₩8,000 |
This excludes card purchases, distance supplements, early-morning discounts and transfers treated as part of one journey. Use your planned routes for the real budget. An adult’s pass comparison also needs recalculating for a child: our Climate Card versus T-money guide explains the cost categories, but its adult-fare examples are not a child’s break-even calculation.
Check the setup before your first sightseeing day
- Keep each card identifiable. Use a name label or different sleeve so an adult does not accidentally pick up the child’s registered card.
- Keep phone and physical-card instructions separate. If an adult uses mobile T-money, a separate physical card for the child keeps that child’s registration easy to identify. Do not assume these plastic-card steps describe Apple Wallet or another app’s registration process.
- Question an unexpected fare with the route details. A charge above the base fare can reflect the journey, not necessarily failed registration. Ask staff to check both the card category and the trip before changing the setup again.
- Treat unused balance separately from fare spending. Our T-money refund guide helps you choose a refund counter by the remaining balance before leaving Korea.
The useful order is buy the right card, register the child’s birth date, confirm when the discount applies, then budget the journeys. Loading more money cannot fix the card’s age category.