Detectives are treating the discovery of a woman's body in the Oxford Canal as unexplained.
Boat users at Shipton-on-Cherwell near Kidlington alerted Thames Valley Police on Tuesday morning.
The woman is believed to be in her late-50s or early-60s. Post-mortem tests are due to be carried out later.
Specialist search and rescue officers have been investigating the scene. Officers have reopened the canal and are appealing for witnesses.