You can use your Youth Card in any class any day of the week on Intercidades, Regional and InterRegional services.
All you have to do is show your Youth Card when you buy your ticket and the to the ticket collector on the train.
CP Services: Intercidades | Regional and InterRegional
This discount cannot be used in conjunction with any other discounts or special offers. Prices rounded up to the nearest 50 cents.
These tickets can be refunded and reissued.