The sun shone down on Buccleuch Dock as hundreds of people assembled to wave their flags at the third Astute class submarine - Artful.
The 7,400 tonne hunter-killer submarine edged her way from Devonshire Dock where she has been moored until today.
Artful's exit attracted hundreds of people who lined the dock to bid their final farewell to the precious boat.
Ben Smith, 33, of Brighton Street, made his way to Michaelson Road to catch a glimpse of the boat he has worked on for the past two years.
He said: "I came to watch it move because I worked on her for two years.
"It's great and I love my job.
"It's one of the most challenging engineering projects in the world so I'm awfully proud of it."
Harry Robinson, from Broughton, said: "It's the first one I've seen.
"I saw the bridge up so came to have a look.
"It's interesting - it's not often you see something like this.
"It's a huge thing for the area."
Luke Smith, 30, from Dalton, added: "It's fascinating to see.
"It doesn't happen often.
"It's amazing when you think of all the work that's gone into it.
"BAE is the main employer here so it means a lot to all the people here.
"It's something Barrow can be proud of."
Catherine Jukes waved the submarine off from Michaelson Road with her baby daughter.
She said: "My partner works at BAE and I thought it would be interesting and something our daughter could watch.
"Nothing really happens in Barrow and it's something we can do that's a bit different."
Gavin Williams, 48, from Dalton, said: "My wife works at BAE so it's a big thing for me.
"It means jobs for the town and security and hopefully that money will be reinvested back into the town.
"It's amazing - they're fascinating things."
When Artful finally leaves Barrow she will make her way north to Her Majesty’s Naval Base Clyde, in Faslane, Scotland, where she will undergo sea trials under the control of her commanding office, Commander Scott Bower.
As the submarine passed through Buccleuch Dock, Ann Stewart, 66, from Barrow, brought out all the family for a rather emotional farewell.
Clutching her Union Flag she said: "It's always special when it's built in Barrow.
"It's a proud day for us all.
"Also my grandson has just passed out from the Navy so he'll be a submariner one day so I'm very proud.
"It's just such a proud day for all of Barrow.
"It shows people what we can do."