Unaccompanied children: On Eurostar, all children under 12 must travel accompanied by an adult, and unaccompanied children from 12 to 16 require a consent form signed by their parent or guardian. See www.eurostar.com for details.

Yes, Eurostar does check the age of passengers, primarily through the mandatory passport and security checks that occur before you board the train. Because Eurostar travels between the UK and the European Union, every passenger must pass through border control where their official travel documents (passport or national ID card) are scanned; these documents clearly show your date of birth. Additionally, if you have purchased a "Youth" ticket (for those aged 12 to 24) or a "Child" ticket (for those aged 4 to 11), staff at the ticket gates or on the train may ask for proof of age to ensure you have paid the correct fare. If you cannot provide proof of age and appear significantly older than the ticket category allows, you may be required to pay the difference between the discounted fare and a full-price "Adult" ticket on the spot. It is also important to note that children under 12 must travel with an adult, and those aged 12 to 15 require a specific "Unaccompanied Minor" form and parental consent, which is verified by staff during the check-in and boarding process at the station.