A team of about 80 volunteers had been working shifts across three trenches ahead of a £2million re-vamp of the area.
Lead archeologist Gavin Glover, from Network Archeology, said: “The preservation here is some of the best in the country.
“Because the ground is damp, it provides perfect conditions for organic remains like leather and wood and bones.
“Leather is common in Boston, but nationally it is very rare because items usually perish. It’s fantastic when you find it.”
In addition to dozens of shoes, others items found included medieval pottery and a 16th century nit comb.
Pictured are some of the volunteers from the Big Dig project.