Hello,

Taken from

http://www.qatarairways.com/global/e...-carriage.page


2. Validity
2.1 Period of Validity
The period of validity for tickets issued at normal one way, round or circle trip fares shall be one year from the date of commencement of travel, or, if the first flight coupon is open dated, and/or unused from the date of ticket issue thereof.
Where one or more portions of a ticket involves an excursion or other special fare having a shorter period of ticket validity than indicated above, such shorter period of validity shall apply only in respect to such excursion or special fare transportation.


However, it is worth noting that promotion fares (O,Q bucket) tend to only have a six month validity. This can be found on the detailed fare rules tab when making a booking.