Police are searching the Aire and Calder canal after clothes were found next to the waterway at Woodlesford.
The clothes were discovered by a member of the public on a fishing platform at the bottom of Pottery Lane at about 0600 BST on Thursday.
West Yorkshire Police said divers were searching a stretch of the canal.
The force said there was nothing to suggest the owner of the clothing had come to any harm but they needed to be traced as soon as possible.
Det Insp John Higson, of City and Holbeck CID said: "lt is crucial that we trace this person as soon as possible so that we can establish that they are safe and well."
The clothes are a pair of light blue jeans in waist size 34, a white Lonsdale polo shirt with a blue motif on the front and an image of a lion on the back, and a pair of white K Swiss trainers in size seven.
Anyone with information is asked to contact West Yorkshire Police.