Two inches of river water seeped into the dining area of The Bull's Head, in Strand-on-the-Green, Chiswick.
But Barbara Smith, who has been landlady at the 18th century pub for six years, described it as "a bit of fun" and assured it was no great cause for concern.
"We had to move an elderly group of people off one areas of our dining yesterday," Mrs Smith told the Standard on Monday.
"We're so used to it happening, but bless them they felt a bit like there were in the Titanic - I think that was the comment - so we moved them."
With high steps and windows, the original pub building is protected from flooding. But around 10 times a year, the Thames rises to the windows of old fisherman's cottages acquired by The Bull's Head in the 1970s, which now form its dining area.
The glazing remarkably withstands the water, but several times a year river water seeps through the wall and into the dining area.
"But we put a slate floor in that room, so we just mop it up and it's all just a bit of fun," said Mrs Smith.
"The Thames comes up above our windows, we get people canoeing along the towpath. It really is marvellous.
"It's wonderful. Even the locals still love it. The tourists and everybody comes out and takes pictures.
"We have got a back entrance, but we joke and say [to customers] 'I'm really sorry, you're marooned in the pub for the afternoon'."
Mrs Smith describes watching the Thames' tidal changes as "amazing".
"It's 15 to 20 feet of water every day which comes up and down," she said. "I still can't get over it, to be honest. It's stunning. We're so lucky."Quite a lot of the year the tide comes up twice a day over the towpath.
"In the winter people sit on the tables and just wait for it to go down, and in the summer people just paddle about in it. It's beautiful."
The Bull's Head is around 400 years old, and is said to have been licensed in 1772.
Flood warnings were in place along the south coast of England, where a major incident has been declared in Hampshire and the Isle of Wight.
Across the south coast, an amber warning runs from 6am to 5pm on Thursday with winds expected to reach 70mph to 80mph, with the potential for 85mph and large waves.
A further amber warning is in place until 11am in Cornwall and Devon, with the Met Office predicting Storm Ciaran will bring winds of 75mph to 85mph, with 65mph to 75mph gusts inland.