KTX under-6 fares separate free accompaniment from an assigned seat. A child can travel without a separate seat under Korail’s rule, but an assigned infant seat costs 25% of the applicable fare after the published 75% discount.
Check the seat, not just the age
- The free allowance is one under-6 child per accompanying adult, without a separate seat.
- A separately assigned infant seat has a discounted fare.
- A 75% discount means paying 25% of the applicable fare portion.
For a longer family journey, that distinction is worth pricing before choosing the free option. The useful comparison is the extra cost of an assigned place for the child, not a vague choice between “free travel” and a full-price adult ticket.
KTX under-6 fares: one adult, one unassigned infant place
Korail’s public-discount rules, checked September 7, 2026, allow one child under 6 per adult to accompany the guardian without a separate seat assignment. An infant ticket is required if a separate seat is assigned or if the number of under-6 children exceeds one per adult.
The same page distinguishes children age 6 through 12, who receive a 50% fare discount. It also says public discounts do not combine with commercial discounts such as internet specials. Do not subtract 75% from an already discounted promotional price unless the actual booking terms explicitly support that calculation.
| Your party’s situation | Published rule | Budget implication |
|---|---|---|
| One adult and one under-6 child, no separate child seat | Within the one-child-per-adult accompaniment rule | No separately assigned place for the child. |
| Under-6 child needs a separate seat | Infant ticket at 75% off the fare | Price the child’s ticket; do not assume an empty seat will be available. |
| One adult and two under-6 children | The second child exceeds the free-accompaniment allowance | Include an infant ticket for the additional child. |
| Child is 6 through 12 | 50% fare discount | The under-6 allowance no longer applies. |
What the extra seat adds: a model, not a route quote
Suppose the applicable undiscounted fare is ₩60,000. At a 75% discount, the modeled infant fare is ₩60,000 × 0.25 = ₩15,000. For two adults paying that assumed fare and one under-6 child, the fare-only total is ₩120,000 without a separate infant seat, or ₩135,000 with one.
That is a ₩15,000 increase, or 12.5% of the two adults’ modeled total—not a 25% increase in the whole family bill. The distinction helps put the seat decision in proportion.
These figures are arithmetic examples, not a Seoul–Busan quote or a promise about a particular departure. Route, train, accommodation class, other charges and the booking channel can affect the amount shown. Use the infant-ticket total in your actual booking before paying.
“Free” should not depend on finding an empty seat
A plan with no separate seat assignment should still work if every assigned seat is occupied. If it only works when the neighboring seat happens to stay empty, you have not really compared the two options—you have assumed the main benefit of the paid option at no cost.
We would therefore price the infant seat first for a longer journey, then decide whether the saving is worth sharing the guardian’s space. For a short journey, a family may reasonably value the saving more. This is a comfort-and-budget judgment, not a safety assessment or a guarantee about how a child will travel.
Check the passenger count and seat count separately
Before payment, check each child’s age on the travel date, how many adults are accompanying them, and which travelers have actual seat assignments. Selecting the right age category is not enough if the resulting reservation does not match your intended seating arrangement.
For travel over the coming months, the comparison remains useful while Korail’s published discount remains unchanged. A fare-rule change or a special product with different conditions would require a new calculation. The actual ticket terms take priority over the example above.
Holiday booking windows are a separate question from child fares: see the 2026 Chuseok KTX booking and payment dates. Do not carry this KTX rule over to the Seoul subway’s child-fare policy or the AREX Express versus All-Stop family comparison; each service has its own conditions.
Checked September 7, 2026. Korail supplies the age and discount rules. The ₩60,000 input, family totals and seat-selection evaluation are K-Trend’s illustrative analysis, not a live fare quote.
Photo: A KTX-Sancheon train at Seoul Station in 2017; seat eligibility is determined by the current ticket rules. Chinmayamahapatra · CC BY-SA 4.0. Resized and converted to WebP without cropping or retouching. View this photograph.
