It stands out among Saint Petersburg metro lines for two reasons — its stations are almost exclusively of "Horizontal Lift" type and it has the longest inter-station tunnels in the entire system.

Metro officials originally intended to add stations in-between the existing ones, but those plans were later abandoned.

The line cuts Saint Petersburg centre on an east–west axis and then turns southeast following the left bank of the Neva River.

Admiralteyskaya was opened in 2011 between Gostiny Dvor and Vasileostrovskaya and became a transfer to Line 5.

The extension of the line north to Novokrestovskaya and Begovaya was opened in 2018.