Do I need to be under 26 at the time of booking or time of departure for SAS youth tickets? I am 25 but I will be 26 when I plan on going on this trip, do I still qualify for the youth rate?
You need to be under 26 at the time of departure.
Source: Tweet by official SAS twitter account.
(Also @LassiUosukainen pointed out in a comment: If you enter the correct birth date the system does not let you continue if you are too old.)
It is very likely that you might be challenged, as you need to present your id in order to board with a SAS Youth Ticket:
Eligibility: Valid for youth 0-25 years of age. Youth under 12 years must travel with adult 16 years or older. Fare not valid for unaccompanied minors. Passengers must present a valid ID at the time of ticketing and at the gate.
ID required: Valid passport must be provided as a proof of your age when boarding.
Visit the SAS web site and indicate your country location; selecting Contact offers the country-specific information to query the company directly and eliminate any uncertainty and possible interruption of your travel plans.