The B5424 follows the original, pre-bypass route of the A565 through the town of Formby in southwest Lancashire. The bypass was opened on 10 December 1938.
Starting at a roundabout on the bypass the road heads west then north to enter the Formby suburb of Little Altcar. It heads north through town along Liverpool Road and soon reaches a roundabout on the edge of the town centre. The road turns right here then bears left on reaching the western end of the B5195; that road is signed as the direct route back to the bypass and so on to Liverpool or Southport.
We now head north along Church Road, which is largely residential. Soon after passing the URC a mini-roundabout is reached where we bear right onto Ryeground Lane. A zigzag left then right takes us onto Southport Road, with the B5424 ending soon afterwards at a roundabout at the northern end of the A565 bypass.