Foggy Bottom–GWU uses a simple island platform layout: one platform with a track on each side. Track C1 carries eastbound trains to Template:Wmata and Largo whilst track C2 is used by westbound trains to Template:Wmata, Template:Wmata, and Template:Wmata.<ref>{{#invoke:citation/CS1|citation
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}}</ref> As with all stations on the Metro, there are platform edge lights to warn passengers of incoming trains.
In 2008, WMATA installed red-colored LED lights at Foggy Bottom–GWU and other busy stations after a successful pilot at Gallery Place.<ref>Template:Cite press release</ref> There is a 22 coffer "waffle vault" ceiling at Foggy Bottom–GWU as it was one of the first stations to be built in the system; later underground stations abandoned this design for a simpler concrete arch.
There is a single mezzanine located at the center of the platform.<ref>{{#invoke:citation/CS1|citation
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}}</ref> Escalators from here allow passengers to descend to platform level or to the sole entrance and exit of the station at the northwestern corner of I and 23rd Streets.<ref name="map">{{#invoke:citation/CS1|citation
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}}</ref> A total of two elevators and six escalators (three between the street and mezzanine and three between the mezzanine and platform) are currently in use at the station.<ref>{{#invoke:citation/CS1|citation
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In 2007, WMATA released a report detailing the potential to add a second entrance to the east side of the platform, serving the intersection of 22nd and I streets.<ref>{{#invoke:citation/CS1|citation
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}}</ref> No further action has been taken to construct this entrance, through the land proposed to host the surface aspect remains unbuilt upon.