Barry Dock RNLI issued the warning as warmer weather draws more people and their pets to the coastline.
The advice follows incidents involving dogs getting into difficulty near cliffs, rocks or the water’s edge.
A spokesman for Barry Dock RNLI said: “Heading for a walk along the coast with your dog this week?
“With the warm weather bringing more people to the coastline, Barry Dock RNLI is reminding dog owners to stay safe near cliffs, rocks and the water’s edge.
“Every year, lifeboat crews and coastguard teams are called to incidents involving dogs that have got into difficulty along the coast.
“And what’s the dog that gets into difficulty the most around our UK coastline According to the Dog’s Trust, it’s a Springer Spaniel!”.
Barry Dock RNLI recommends keeping dogs on leads near cliff edges and fast-moving water, avoiding walks during the hottest part of the day, bringing fresh water, and checking for beach restrictions.
Barry Dock RNLI are advising people that if their dog gets in trouble, they should not go into the water or climb down cliffs after them.
They should, however, call 999 or 112 and ask for the coastguard.
A spokesperson said: “If your dog gets into trouble, don’t go into the water or climb down cliffs after them. Call 999 or 112 and ask for the Coastguard.
“We love our dogs and a few simple steps can help keep you and your four-legged friend safe.
“Keep dogs on a lead near cliff edges and fast-moving water; be aware of incoming tides and changing conditions; take fresh water for your dog and avoid walking them during the hottest part of the day; check local beach restrictions before visiting.
“Enjoy the sunshine safely and help us keep everybody safe along the coast this summer”.
As the Vale of Glamorgan is hit by a red weather warning for extreme heat, Barry Dock RNLI are also advising people not to walk their dogs during the hottest part of the day.
