Flagstaff, like the other two underground Loop stations (Parliament and Melbourne Central) has four platforms on two levels, each one serving a separate group of rail lines that leave the Loop and radiate out into the city's suburbs.
Flagstaff, like the other two underground Loop stations (Parliament and Melbourne Central) has an underground concourse with toilets, ticket machines, a booking office, and ticket operated gates. The four platforms serve a separate group of rail lines that leave the Loop and radiate out into the city's suburbs.