If you are aged up to 25 (inclusive), save on your journeys and keep more money for what you want to do. Apart from that if you get an Alfa Pendular or Intercidades ticket you can also get discounts on a series of activities from partners such as hotels and parks.
See more here.
CP Services: Intercidades | Alfa Pendular | Regional and InterRegional
You can use this discount in any class, any day of the week. Just show official ID with proof of your age such as a Citizen car, ID card, driving licence or passport.
You have to prove the ticket is yours and you have the right to the discount by showing an official ID document or certified photocopy of it
These tickets can be reissued or refunded.
This discount cannot be used along with any other special rates. Alfa pendular and Intercidades prices rounded up to the next 50 cents.
Young people aged 26 or over can still enjoy the Cartão Jovem discount for individual journeys.