Within Bath the A36 acts as a ring road on the southern side of the river, from the junction with the A4 at Newbridge to the west of the city.

Another link to the A4 on the eastern side at Cleveland Bridge, which provides a route to the M4 motorway via the A46, is highly congested.

The road passes near a number of towns and a city, including Frome, Warminster, Wilton and Salisbury in Wiltshire, and Totton in Hampshire, on the western outskirts of Southampton, where it meets the M27 motorway and the A35.

Just south-east of Salisbury the largest dualled section runs for about 4 miles (6 km), bypassing the village of Alderbury.

Then, the road is briefly dualled from its roundabout with the A3090 to the M27 motorway (junction 2) – this part of the road is erroneously thought by some to have been previously known as the A36(M); prior to the opening of the Totton Western Bypass on the other side of the junction, it was named as a spur of the M27, and hence is built to motorway standards.