About 250 passengers and crew were stranded on ferries after a bomb was discovered in the River Mersey.
The bomb was dragged out to sea by a Royal Navy team
The 500kg (1,102lb) World War II device was found by the Royal Navy at Twelve Quays dock, Birkenhead.
The Mersey Viking and Dublin Viking were finally allowed to berth on Tuesday afternoon after waiting since the early hours of the morning.
Navy divers are moving the 7ft (2.1m) German penetration bomb out to deeper waters in the Irish Sea to detonate it.
The Norfolk Line ferries had travelled to Liverpool from Dublin and Belfast.
The Wallasey tunnel and a Merseyrail line were closed for about 45 minutes when the operation began, but Merseytravel said disruption was kept to a minimum.
The Mersey Viking, which has 64 passengers and 55 crew, and the Dublin Viking, which has 81 passengers and 46 crew, had arrived in the early hours but were unable to dock.
Commander Chris Davies, from the Royal Navy, told the BBC that the bomb was a German air-drop explosive.
He said: "It would cause a significant blast if it detonated.
"The measures that we have put in place with Merseyside Police and the Liverpool port authorities ensure public safety and the remainder of the operation is to minimise disruption to the city and the Port of Liverpool.
"We routinely carry out these operations and they [the Navy team] are towing the device at a sufficient length, so that if it did detonate, they would be safe."
A Navy spokeswoman said a lifting bag was attached to the bomb to raise it to a depth of 3m (9ft).
"They then attached a tow line and are currently towing it at slow speed to North Bar Light, a safe area identified by the coastguard," she said.
"Once they get there, a diver will go down and attach plastic explosives to the device in order to detonate it."
Royal Navy spokesman Neil Smith said the bomb was "one of the most powerful and destructive" bombs dropped on the city during WWII.
"The Germans dropped this bomb to try and destroy the dockside in Liverpool," he said.
Mr Smith said the city was a strategic target because it was at the receiving end of the Atlantic convoys that brought war relief to the UK from the United States.