Originally it started on the A21 at Southend, near Catford, before heading south along what is now the A2015 into Beckenham. This section of the B230 was upgraded in the 1920s and so the road now starts in the centre of Beckenham at a traffic-light junction with the A2015. It heads east along Bromley Road (which was originally unclassified; the B230 multiplexed along the A222) and crosses the A222, also via traffic lights.
Now heading south along the residential Wickham Road the B230 meets the B251 at a roundabout where it passes the famous Chinese Garage, a former petrol station (now car dealership) built in an eastern style. The road then crosses another couple of roundabouts leading to the Park Langley estate. The road briefly becomes semi-rural before it goes under a railway bridge and ends at another roundabout on the A214.