The victim, aged in her 20s, was found up to her waist in the mud by firefighters called to the river near Great Union Street.
Emergency services had received the initial call at 01:18 BST and the woman was pulled out at 01:51.
The woman was treated at the scene by paramedics before being taken to Hull Royal Infirmary.
A Humberside Fire Service spokesman said she had had a lucky escape.
"It could have been a lot worse," he said. "An hour or two in the mud and cold at that time, you certainly wouldn't want to be left there until morning."
The next high tide, 6m (19.7ft) deep, was at 12:42 on Wednesday.
The fire service said it launched a river rescue from Kingswood, and used a sled, ladder and lines to pull the woman out, which took around 25 minutes.
The river Hull is tidal, leaving large mudbanks at low tide.
A woman had to be rescued from a mudbank on the River Hull after she became stuck.