After clearing security, the public enters a grand hall beside the entrance from Rideau St. The hall is a transition space to the waiting room below, a main space to all the historical phases of the building. This foyer is equipped with an intricately-detailed rectangular coffered ceiling lined with a pale orange trim, and portraits of important contributors to Canada that decorate the off-white walls. The space has some natural light from the entrance doors, but chandeliers line either side of the space which allows more light to reflect off the off-white masonry walls and light grey stone floors. In between the grand staircases to the Waiting Room, there is a platform overlooking the Waiting Room space which doubles as the ceiling of the tunnel connection to the Château Laurier. Continuing the language of the exterior, there are two large Doric columns framing the lookout platform and two pilasters along opposing walls beside the staircase.

The vestibule to the Senate in the Centre Block is a lot narrower than the current foyer. Similar in height, this space is an arched transition space to the Senate Foyer. The space is equipped with grey masonry walls and a dark brown carpet that leads to a staircase connecting to the foyer. Some natural light comes through the stained glass Diamond Jubilee Window ("Senate Virtual Tour" 2019) above the entrance and one chandelier reaches down into the space to provide artificial lighting. Two flags are located at the door representing Canada and Ontario, and a Senate Mace sculpture is located under the window to pay tribute to the significance of the mace in the Senate court ("Senate Virtual Tour" 2019). 

While both spaces are transitions to a grander space, the Senate of Canada Building’s entry hall allows for a bit more freedom in movement than the straight, narrow vestibule in the Centre Block. Since the entry hall is overlooking the Waiting Room it also allows visitors to take in the space before entering, while the previous vestibule is below the Senate Foyer, so that space is not truly appreciated until the stairs are ascended. Both spaces continue their respective architectural languages into the interior, the Senate of Canada with the Beaux-Arts style and predominantly white materials, and the Centre Block with the Neo-Gothic style and predominantly grey materials.