Under 12 years old: must travel with a responsible person aged 16 or older.

12 to 15 years old (inclusive): can travel on their own on trains departing between 06.00 and 17.00 local time, as long as they’ve got a fully completed Eurostar unaccompanied minor form. This must be signed by their parent or legal guardian (or by a responsible adult given consent by the parent or legal guardian) at the station in the presence of a member of the Eurostar team.
 
Children under 16 cannot travel unaccompanied on our direct trains to or from the Netherlands. 

The child will need to keep this signed form with them throughout their journey and show it to the onboard team if they’re asked. When the parent or legal guardian gives written consent for the young person to travel, they accept and agree that the young person will travel unaccompanied and be treated as an adult passenger (i.e., the young person will not be supervised by a member of the Eurostar staff) for the entirety of the trip. The responsible person must also ensure arrangements are in place for the young person to be met on arrival. 

16 to 18 years old: can travel by themselves, as long as they’ve got all the usual travel documents and meet all the legal requirements (please see below).

French citizens and foreigners living in France
 
Anyone under 18 who is a French citizen or a foreigner living in France must complete an Authorisation de sortie de territoire (AST) form before they travel alone or without their parents.
 
This applies to journeys from France.
 
Documents your child will need
Passports are mandatory for all passengers, including children

Up to 16 years old	Up to 18 years old
All unaccompanied minors Eurostar ticket Passport Eurostar unaccompanied minors form signed by parent   French citizen or a foreigner living in France who is leaving France: As above, plus: Authorisation de sortie de territoire (AST) form signed by parent Photocopy of the passport of the parent who has signed the AST form	All unaccompanied minors Eurostar ticket Passport        French citizen or a foreigner living in France who is leaving France: As above, plus: Authorisation de sortie de territoire (AST) form signed by parent Photocopy of the passport of the parent who has signed the AST form