The £5.4 million Peppermint Junction in Holbeach has been fully opened, three months ahead of schedule.
Work began on the junction between the A17 and the A151 in May 2017, and was due to be completed in February 2018.
The £5.4 million scheme has seen construction of a new roundabout to replace the former T-junction at the A17/A151.
A second roundabout has also been constructed, opening up land for a South Lincolnshire Food Enterprise Zone.
Councillor Colin Davie, Executive Member for Economic Development, said: “It’s absolutely fantastic to have a road scheme delivered early and delivered on budget.
“It’s going to be a game changer for this part of the world and it’s obviously closely linked with the food enterprise zone and the expansion of the University of Lincoln enterprise site.
South Holland District Council’s Nick Worth, added: “I have been planning for this since 2008, so I am absolutely delighted that it’s finally completed.
“It’s making journeys safer onto the A17 and improved traffic flow and made the town more pedestrian friendly, it’s a fantastic project.”