Staff at Oxford's Isis Farm House decided to close early yesterday, at 4pm, after water started to creep towards the entrance gate.
Owner Jonathan Price said the Iffley pub had been accessible along the towpath and customers had still dropped in – but wearing Wellington boots.
He said: “We were surrounded by water and our front door was about 10cm above water level.
“If early January is anything to go by it will take 48 hours to come. Thursday’s rain we are expecting to be at our front door late Tuesday night.
“We have a pretty good plan in place. Most of the action is outside where our wood supply starts escaping so we net it all up to stop it floating away.
“Inside we keep an eye and move things as necessary. It’s good fun.”