Cops say an R train flasher is on the loose.

A woman on a northbound R train at the Grand Avenue station in Elmhurst saw more than she wanted on March 2.

A man boarded the Queens-bound train at around 7:40 a.m. and sat down in front of the woman before exposing himself to her.

The man ran off the train after it pulled into the next station at Woodhaven Boulevard.

The woman snapped a picture of the flasher, who police described as a Hispanic man about 5-feet-5-inches tall and weighing about 140 pounds.

Authorities ask that anyone with leads on the suspect call the NYPD's Crime Stoppers Hotline at 800-577-TIPS or text tips to 274637 (CRIMES). then enter TIP577.