"December 2 is the last day to buy and activate discounted 30-day tickets. After that, 30-day tickets will be sold at the regular price," Storstockholms Lokaltrafik (SL) writes on its website.
Anyone who buys a monthly pass at the beginning of November will have time to take advantage of the discount one last time in December.
Travelers whose 30-day ticket expires after December 2 may miss out on the discount for the rest of the month. This is because SL's app does not allow two active period tickets at the same time.