The A1243 serves the suburbs of Great Yarmouth.
The road starts at a roundabout on the A47 (formerly the A12) in Southtown, on the right bank of the River Yare. It heads northeastwards along the D2 Pasteur Road which runs through an out-of-town retail park. We join the original route of the A12 as the building on the left become older, then the road narrows to S4 as it crosses the bascule Haven Bridge into Great Yarmouth itself. The road TOTSOs right at traffic lights on the far side; left is the B1141 and we now follow that road's old course through the town.
We run alongside the River Yare on Hall Quay and South Quay and reach the other end of the circuitous B1141 at traffic lights. As we reach the suburbs road and river separate and we now have buildings on both sides. Continuing on the road appears more industrial.
Now on South Denes Road - and looking nothing like a classified road by this point - we reach the original southern end of the B1141 and continue on into the docks. The A1243 ends without ceremony at the "no through road" sign, with the road ahead now unclassified, although on the ground there is no change in condition.