score:6
For a standardized American breakfast:
McDonald's, Im Tal 6 (near Marienplatz) opens at 6:00; Hauptbahnhof (downstairs near S-Bahn) open 24/7.
Burger King, twice at Hauptbahnhof, open 24/7.
Starbucks, Hauptbahnhof, opens at 3:30.
Upvote:6
After some searching on Foursquare and Google Maps I've found the following places:
Open from 6AM to 10PM and located 800 meters from the heart of Oktoberfest. The address is GoethestraΓe 40. Judging by the photos, the place serves eggs, salad, sandwiches and a variety of bakery.
Open 24 hours per day and located near Munich Ostbahnhof, 4 km from Oktoberfest. The address is: Orleansplatz 10. The menu includes donuts and coffee, for about 1EUR per donut.