We can access the one season prior, but that’s it. This means that you have the approximately 3 months that the season is live, plus the approximately 3 month duration of the season following, to redeem any earned pass rewards. Please keep in mind that paying for the season pass does not entitle you to the rewards, it simply gives you access to earn the rewards during the active season. It is up to the players to unlock, and redeem items, while they’re available.