Scientists believe the impressions were left by flesh-eating three-toed theropods, plant-eating ornithopods and heavily-armoured ankylosaurs around 110 million years ago.
They were discovered in the cliffs and the foreshore of Folkstone, Kent, by Philip Hadland, collections and engagement curator at the Hastings Museum and Art Gallery.
Mr Hadland said: “Back in 2011, I came across unusual impressions in the rock formation at Folkestone. They seemed to be repeating and all I could think was they might be footprints.
“This was at odds with what most geologists say about the rocks here, but I went looking for more footprints and as the tides revealed more by erosion, I found even better ones.
“More work was needed to convince the scientific community of their validity, so I teamed up with experts at the University of Portsmouth to verify what I’d found.”
He said it proved that it was possible for “almost anyone to make a discovery that adds to scientific knowledge from publicly accessible geological sites.”
The footprints discovered in the area belong to at least six different species of dinosaur, according to a report published in the Proceedings of the Geologists’ Association.
Among the findings were a “trackway” of six footprints from the same animal, likely to be an ornithopodichnus. They are similar in size to an elephant footprint.
The largest footprint measured 80cm wide and 65 long and has been identified as belonging to a dinosaur similar to the Iguanadon.
Much of Britain lay beneath a shallow sea during the Late Cretaceous period, but the study shows that this rock formation in Folkestone was inter-tidal – meaning it was exposed during low tide.
Experts believe the dinosaurs took advantage of tidal exposures on the foreshore to forage for food or to follow a migration route.
David Martill, professor of palaeobiology at the University of Portsmouth, said: “This is the first time dinosaur footprints have been found in strata known as the ‘Folkestone Formation’ and it’s quite an extraordinary discovery because these dinosaurs would have been the last to roam in this country before becoming extinct.
“They were walking around close to where the white cliffs of Dover are now – next time you’re on a ferry and you see those magnificent cliffs just imagine that.”