The campaign, which launches on Monday, aims to raise awareness of the state's 7,500 miles of pristine coastline and encourage UK consumers to ditch their European holiday for a trip to Western Australia.
The ad, featuring a Spanish matador fighting a kangaroo, reads: "We can't blame Costa Brava for using a picture of a beautiful Western Australian beach in their tourism advertising.
"We have enough to share around, so we don't mind. If you want to experience the real thing, visit westernaustralia.com for some great holiday deals. Western Australia -- It's Juan great holiday destination."
Tourism Western Australia's campaign comes after Costa Brava Pyrenees Tourism officials were caught earlier this month using an image of a Western Australian beach to illustrate a strip of the northeastern Spanish coastline.
The photograph of a man and a boy standing on a white beach, staring out into a clear blue sea was actually taken on City Beach in Perth.
Christie Lord, marketing manager for Tourism Western Australia, said: "It's great to know our beaches are the envy of the world, particularly in Costa Brava. However, those going to Spain in search of the picturesque beach shown in their ads may be disappointed.
"The clean white sand and endless blue skies in the image are only to be found in Perth, where you can actually have a whole stretch of beach to yourself rather than fighting for a patch of sand.
"In the current climate, it's more important than ever to ensure consumers who are inspired by our pristine beaches, know they are West Australian.
We invite anyone who was inspired by the image to come to Western Australia to experience the real thing for themselves."