Its southern terminus is an interchange with the Boulevard Périphérique at the Porte de Bagnolet, and its northern terminus is an interchange with the A1 near Aéroport CDG.

The A3 is 18 km long, and forms a part of European Route E15.

The first section of the roadway opened in 1969 between the Porte de Bagnolet and Bondy.

The A186 Autoroute was originally planned to connect the A3 with the A86 - however this spur was never completed.

It closed in May 2019, and will be converted into an extension of Île-de-France tramway Line 1 by 2024.