At the Rosbrien interchange in Limerick the route continues as the N18 dual carriageway to Galway, Shannon and Ennis.

The N7 route continues in a south-west direction with 3 lanes of traffic each way towards Naas for approximately 15 km (9.3 mi).

Construction of the third lane commenced on 4 January 2005 and concluded on 14 August 2006 (thumbnail left); having been originally dualled between 1963 and 1968.

Traffic for Clondalkin to the north and Tallaght to the south leave the N7 by slip roads connecting to the R113.

The N7 continues southwards to bypass Citywest, Saggart, Rathcoole, Kill and Johnstown in County Kildare.

These locations are all served with grade-separated interchanges which were constructed as part of the upgrade works completed in the mid-2000s.

The route continues in a south-west direction bypassing the towns of Naas, Newbridge, Kildare, Monasterevin and Portlaoise.

South of Portlaoise the M8 diverges from the M7 to Cork and the south at junction 19 with the M7 continuing south-westwards bypassing the towns of Mountrath, Borris-in-Ossory, Castletown (County Laois), Roscrea, Moneygall, Toomevara, Nenagh and Birdhill.

Prior to the year 2000, only short sections of the N7 were of motorway or dual-carriageway status: As part of the National Development Plan undertaken by the Irish Government from the mid-2000s onwards; work took place to link existing sections of the M7 and extend it to Limerick: The junctions on the Naas Bypass and Newbridge Bypass sections of the M7 were previously numbered J7-J11 (now renumbered Junctions 9–13), in the expectation that an M7 motorway would be built along a new alignment.