A KTX seat for a child under six has a different fare from a seat for a six-year-old. KORAIL lists a 75% infant fare discount, leaving 25% to pay, while the ordinary child discount leaves 50% to pay. If your toddler needs a separate seat, check the infant category before paying the older-child rate. Free accompanied travel does not reserve a seat for the toddler.
There is a booking complication: on October 22, 2026, the official English reservation page showed Adult (13+) and Child (6–12 years old) in its passenger selector, with no infant option visible. The published discount and the choices available on that screen are separate things. Here is how to compare your family’s seat needs and handle that gap.
Which age and seat rule applies?
The Korean KORAIL FAQ, checked October 22, 2026, gives the precise age boundaries and the free-accompaniment limit:
| Traveler | Fare rule | Separate assigned seat? |
|---|---|---|
| Under 6, traveling free | One child per guardian without an assigned seat | No |
| Under 6, with a seat | 75% fare discount; 25% remains | Request the infant seat ticket |
| Age 6 through 12 | 50% fare discount; 50% remains | Check the ticket’s assignment |
| Age 13 or older | Adult category | Check the ticket’s assignment |
Use the child’s age on the travel date. The Korean wording is 6세 이상 13세 미만: from six up to, but not including, thirteen. The English reservation selector’s 6–12 label makes that boundary clearer than the English FAQ’s broader wording.
The English FAQ, also checked October 22, lists the 75% toddler discount for up to two children per guardian. That is not a promise of two free children: the Korean FAQ separately limits free travel without a seat to one under-six child per guardian. A parent traveling with two under-six children should confirm the second child’s ticket before paying.
These percentages describe the published fare discount. Confirm the complete quote for your train, class and passengers; do not apply the percentage blindly to extra charges or a reseller’s total.
Two adults and one toddler: count the seats
For a family with two adults and one four-year-old, the useful comparison is two reserved seats versus three.
The following is a calculated example, using 100 fare units per adult. These are not won prices or a live quote; the example excludes extra charges and other discounts.
| Seat plan | Family fare units | Assigned seats |
|---|---|---|
| Toddler travels free without a separate seat | 100 + 100 = 200 | 2 |
| Toddler has an infant seat ticket | 100 + 100 + 25 = 225 | 3 |
The infant seat adds 25 units, or 12.5% of the two adults’ combined fare, in this example. Decide whether that extra seat is worth the added amount for your journey. Do not plan to use an apparently empty seat as the toddler’s reserved place.
An older-child fare of 50 units would be twice the 25-unit infant fare. That arithmetic explains why checking the category matters; it is not a reason to enter an incorrect age or a guarantee that every sales channel offers the infant rate.
No infant option on the English website?
Start with the official English booking page, open Passengers, and check the labels currently shown. Our October 22 inspection reached the passenger selector only; it did not establish whether a later screen or every app version offers the infant category.
If you cannot request the correct age category and seat:
- Ask KORAIL which booking channel supports an infant seat for your journey before paying. Its official English site lists +82-1599-7777, with call-center hours 08:00–20:00. Check international calling charges with your phone provider.
- Give the child’s age and state that a separate seat is needed. Ask for the final fare and how to keep the family together. A discounted ticket does not, by itself, confirm adjacent seats.
- Use a station ticket office if that suits your travel plan. KORAIL lists ticket offices as an official purchase channel. Waiting until arrival carries an availability risk; it is not a reservation.
- Check the actual issued tickets. Match the date, train, route, carriage and seat numbers for everyone who needs a seat. Confirm any cancellation or correction cost before buying an alternative ticket.
You can show staff this request:
My child is four years old and needs a separate seat. Can I buy an infant seat ticket and sit next to my child?
아이는 만 4세이고 별도 좌석이 필요합니다. 유아 좌석 승차권을 구입하고 아이 옆에 앉을 수 있을까요?
Replace four with your child’s actual age. Keep the request specific; “a child ticket” can leave the age category unclear.
Finish the family booking plan
Check the KTX booking window before choosing dates around a particular departure. If the train is sold out, our standing and combined-ticket guide explains why a ticket may not provide a seat throughout the trip. Also settle the luggage plan before carrying cases and helping a small child board.
The final check is correct age category → number of assigned seats → family seat positions → complete price. This guide covers ordinary KORAIL tickets; a rail pass or reseller package needs its own terms checked.