You can't tell if a fare is refundable just by fare booking class. The specific fare purchased is identified by 8 character fare basis code which is embedded in Fare Details: line in email receipt. The below is an example with fare basis code VA7NA0MF. The M in second to last letter identifies this as a main cabin fare.


Non-refundable F fares on a SEA-PVR have an N or S in 6th letter of fare basis code, while refundable F fares have a T or R. As an example, a VNNC0NFS F fare is non-refundable, while a VNNC0TFK fare ($100 more) is refundable. These both book into Z booking class.