The road forms a route from the city centre to Cork Airport, and onto the R600 connecting to the port town of Kinsale.

The route runs out of the city centre along the following route: Michael Collins Bridge, Custom House Street, Éamon De Valera Bridge, Albert Street and Old Market Road.

The bridges are across the two diverged parts of the River Lee which flow around the city centre.

The South Link Road brings the N27 from the city centre area out to the N40 Cork South Ring Road at the Kinsale Road Roundabout, a three lane signal-controlled non-symmetrical roundabout (with 5 exits) that has been upgraded to a grade-separated interchange in relatively recent times, and referred to as the Magic Roundabout.

The section of the N27 between the Kinsale Road Roundabout and Farmer's Cross was improved during the mid to late 1990s.