The A46 starts at Isaac's Hill roundabout with the A1098 and the A180. It meets the A1031 at a roundabout and passes the King George V Stadium on the right. It meets the B1213 from the right, then crosses the A16 Peaks Parkway where it gains primary status. It heads into Grimsby, meeting the A1243 Bargate (former A16). It meets the B1444 where the road becomes a dual carriageway. It meets the A18 at a roundabout. This was the old terminus of the A46, and what is now the A46 heading east into Grimsby used to be the A18. The road becomes the single carriageway road once again and runs alongside the north part of the Lincolnshire Wolds. It bypasses Irby upon Humber and enters the East Midlands. It bypasses Swallow to the North. It climbs a hill to meet the B1225, A1173, and A1084 just east of Caistor. The road crosses the Nottingham - Grimsby railway at a level crossing. The road becomes very straight and flat, passing through Middle Rasen Plantation and meets the A1103 from the right. The A631 leaves to the right at a T junction. The road bypasses Dunholme to the south then it passes close to the former RAF Dunholme Lodge. It passes the headquarters for Lincolnshire Police on the left. It meets the A158 (for Skegness) and the B1182 (former route into Lincoln) at a roundabout.