17 champions (about 10% of champion roster) are available for free play at any given time. New champions are added to the free champion rotation on the third week following their release.
Riot has introduced various methods to unlock champions in LoL with the following methods:
1
Linking Your Xbox Gamepass Account.
2
Using Blue Essence.
3
Using Champion Shards.
4
Hextech Chests.
5
Champion Capsules.
6
Honor System.
7
Through Prime Gaming.