Can I add "Tyranny of King Washington" to Assassin's Creed 3

Solution 1:

All 3 parts of the King Washington content are included in the season pass, so if you can find that you'll have everything you want, in addition to:

• The Hidden Secrets Pack

It includes three naval memories, one secret location, two outfits, four weapons, two Animi Avatars and two naval-based upgrades.

• The Battle Hardened Pack (multiplayer content)

The pack includes three new Animi Avatars and simulated maps with the new personas including the Coyote Man, the Governor, and the Highlander.

As of September 9th 2019, the Assassin's Creed III Season Pass is available at the Humble store. Note that it will not activate on Steam, but only on Uplay.