You unlock Calendars as you progress! New Summoners get a 31-day Summoner Supply Drop Calendar and a 7-day successive log in Calendar at level 4.
Completing story quests unlocks more, like the 14-Day Uncollected and 7-Day Cavalier. Sometimes, these Calendars will replace older Calendars retiring older versions of the same type to deliver the best rewards for your current game progression.
Reaching Proven status by completing Act 3 unlocks the Progressive Monthly Calendar.
Special Event Calendars have unique requirements announced in the game.
Missing a Calendar despite meeting the requirements? Contact Kabam Support! We will thoroughly investigate your account to determine what occurred.