|Distance:||24.2 miles (38.9 km)|
|Meets:||A1033, B1362, B1238, A1035, B1249, A165|
|Old route now:||A1033|
|Route outline (key)|
The B1242 is the East Riding coast road.
It originally started end-on on the B1241 in Patrington and headed northeast to the coast. This section was renumbered as an extension of the A1033 in the early 1920s and so the B1242 now starts at the end of the A1033 in Withernsea, where the B1362 is also met.
The B1242 heads continues north following the coast, albeit not too closely. Indeed, it starts by heading inland to Roos before going through Aldbrough and then reaching the coast again at Mappleton.
The road continues about half a mile inland to Hornsea and passes very close to Hornsea Mere. After Skipsea it turns away from the sea once again to end shortly afterwards on the A165 at Lissett.