The town has been known to host up to 300,000 tourists in a single weekend.
Mayor Maurici Jiménez announced a new bylaw banning people from going out in public "without clothing or only in their underwear or with clothing or accessories representing human genitals or with dolls or other accessories of a sexual nature."
Violations carry fines ranging from $325 to $1,627.
Jiménez said pre-wedding celebrations have gotten out of hand in the town recently and are threatening the peace of locals.
Platja d'Aro Police Chief David Puertas cited a recent example where a bachelor party used gaffer tape to bind the groom-to-be to a lamp post and disturbed residents by playing loud music long into the night.
The town's new bylaw follows similar measures instituted in Spanish locales including Tossa de Mar, Lloret de Mar, Sevilla, Málaga and Granada.
