From Press Release:
This morning, 343 Industries announced “Halo 3” will be officially joining “Halo: The Master Chief Collection” on PC starting July 14. “Halo 3” marks the fourth title to be released in the collection on PC, and will be available with Xbox Game Pass and on Steam and Windows 10 in addition to its existing availability as part of the collection on Xbox One.
On July 14, Spartans will be able to Finish the Fight between the Covenant, the Flood and the entire human race in the dramatic, pulse-pounding conclusion to the original Halo trilogy. Relive 11 unforgettable missions and fight through 24 multiplayer maps, complete with enhanced Spartan customization and an all-new progression system spanning each game within “Halo: The Master Chief Collection.” What’s more, players can tap into their inner designer with the power of an updated and expanded Forge that allows players to create the multiplayer maps of their dreams and utilize the Theater to commemorate their greatest triumphs.