A man believed to be in his 70s walked into city playground and exposed himself to a group of teenage girls, police said.
The man with grey greasy hair and a large nose, was wearing a beige bomber jacket and was walking a Yorkshire terrier with a blue lead.
The incident happened at around 6.30pm on Sunday, June 17, in a playground off Gareth Close, Thornhill, Cardiff, near the underpass between Derwent Close and Orchard Castle.
The man was seen again two days later in playing fields off Llanon Road, Llanishen, but on this occasion the dog was believed to be a Jack Russell.
A spokeswoman for South Wales Police said: “Thornhill is a safe place and remains a safe place, however this individual needs to be traced and officers are actively looking for him.
“As always we would advise young people to stay with friends when out and about.”
Anyone with information should contact PC Jonathan Edwards from Llanishen Police Station on 07805 301 245 or via 101, quoting occurrence number 6212 0194 631.
Any immediate sightings or suspicious behaviour should be reported to police via 999.