: Blizzard requires you to connect to the internet and log in at least once every

Playing offline provides a "guest" experience with restricted features:

Blizzard officially supports offline play for the StarCraft 2 single-player campaigns (Wings of Liberty, Heart of the Swarm, and Legacy of the Void) and vs. A.I. matches. However, you must first download the game via the Battle.net launcher and log in at least once while online.

If you have recently authenticated online, use these steps to enter offline mode: Disconnect Internet