Ferry passenger Remco van Schellen arrived from the Netherlands at about 08:00.
He said: “When we wanted to leave the ferry terminal with the car, we couldn’t go any further.
“There were people blocking the roads, the roundabout, just outside of the ferry terminal in Dover.
“There were people in black clothing, their faces masked, so we couldn’t see who they were.”
Rafael Pittman, a tour guide from London, said the area had been “absolute chaos” in the three hours that he was there, waiting to pick up a group of tourists who had docked at Dover.
He said: “Passengers didn’t disembark and we couldn’t enter the terminal as it was blocked by freight trucks.
“The hooded protesters arrived en masse, passed the trucks and headed towards the cruise terminal, followed by the police.”
Pittman added that, while the protesters “looked quite frightening”, they were “friendly-ish” and told him that they were protesting against illegal migration.
Lania Tkaczyk, from Cheshire, saw men dressed in black outside her hotel in Dover.
She said she was unable to leave on time to see her two children take part in a Channel swimming relay at nearby Folkestone.
“It was quite intimidating seeing the men head-to-toe in black,” she said.
“Because of the protest I’ve been delayed but I hope to get to Folkstone to see my children soon.”