A section between North Cave and Hull forms the eastward continuation of the M62 motorway and is part of the unsigned Euroroute E20.

At the end of this dual carriageway section, the route meets the M1, and the road continues north along the motorway for one junction then resumes as the A63.

This dual-carriageway section of the former A1, follows the Leeds – North Yorkshire boundary (Ledsham and South Milford), and was built as part of the Brotherton-Micklefield scheme in November 1964 by Dowsett Engineering Construction.

The short section around Barlby follows what was the old East Coast Main Line railway before the Selby Diversion opened in the early 1980s.

An alternative route eastwards from the Selby bypass, to the M62, is the A1041 via Camblesforth, then the A645 past Drax power station.

It passes through Newsholme before bypassing Howden to the west, as Barnhill Lane and Boothferry Road, where it meets the A614 at a roundabout.

Before the M62 opened, the single carriageway A63 was Hull's main route to the South of England, causing many bottlenecks.

The road skirts the southern edge of South Cave, and near Ellerker it crosses the former route (and Ermine Street from Brough, then known as Petuaria, to York) at the A1034 junction.

The 2.5 miles (4 km) Elloughton bypass was built in October 1971, from the A1034 to the Welton/Brough junction passing Brantingham to the west.

[16] The Shell Grand Dale filling station is on the westbound side, west of the Melton interchange.

Near the Albert Dock, there is a fly-over where it rejoins the former Hessle Road next to the Smith & Nephew factory to the south.

The Castle Street section of the road (2011) had significant air pollution problems (NO2 levels),[20] with over 55,000 vehicles per day, and had heavy congestion, having been at full capacity for around a decade; much of the traffic is heavy goods vehicles originating as a result of Ro-Ro activity at Hull Docks.

The road section also was experiencing high accident levels, as well as forming a barrier to local north–south movement within the city centre.

[22] Split level junctions including passing under or over the A63 were considered for the bottleneck at the Mytongate roundabout,[map 1] with additional congestion easing measures, and pedestrian bridges.

In March 2010 the Highways Agency established a preferred scheme – the A63 would be lowered 23-foot (7 m) at the Mytongate bottleneck, and the north south connecting roads raised slightly (3.3-foot (1 m)), creating a split level junction; additionally the eastbound carriageway would be widened, and pedestrian crossings created.

It is prone to congestion due to traffic from the Port of Hull and vehicles exiting Victoria Dock heading into the city centre.

The £1.5 billion project would have a dual carriageway road veering into the estuary and take all of the through traffic from the A63 away from the centre of Hull.