These are the conditions when you travel with children on Eurostar trains: 

Children under the age of 4

• Can travel for free, but he will not have a seat and he will be required to sit on your lap.
• You do not need to add the child during the booking process in this case; anyway, a child fare will be applied automatically.
• If you want them to have their own seat, you must purchase a child ticket.
• if you are going to travel alone with 2 or more children under the age of 4, you must hold one on your lap and purchase for the rest child tickets.

Children aged 4 to 14

• Special fares in Standard class are available for children aged 4 to 11 years old.
• Our youth fares are available to children aged 12 and up.