The institute commissioned the posters in an attempt to address the anxiety many women feel about their own bodies and visiting Spain's beaches over summer.
"Today we toast a summer for all, without stereotypes and aesthetic violence against our bodies," said Montero.
Not everyone was pleased with the messaging.
Some were quick to point out there was a group of beachgoers that were not depicted - Men. Those said that male beachgoers with 'non-standard' bodies should also be celebrated and were also subject to the stigma of beach bod shame.
Left-wing politician Cayo Lara called it a "complete absurdity", saying the ministry was "looking to create a problem that doesn't exist."
Junior equality minister Angela Rodriguez Pam said that while women didn't need approval to go to the beach, some women feel judged by simply being in a public beach.
"Of course we go, but we're assuming we'll attract hatred for showing a body that isn't standard."
Many public figures came out in support of the campaign including journalist and politician Esther L. Barceló.
"Since I was thirteen I have hated the beach," said Barceló, admitting that issues of body shame have made her job appearing on television a "nightmare".
"Don't be like me. Summer is also yours."
Battle of the Beach Bod
The campaign was created with the help of the Spanish Institute of Women and Sexist Advertising Watchdog (OIM). The OIM was founded in 1994 to promote a "balanced non-stereo-typed image of women" in the European media and advertisements.
The "Beach Body" has been a flash point in the summer advertising across the continent.
In 2015 the Mayor of London's office banned body shaming in advertisements after a backlash against weight-loss product using the slogan "Are you Beach Body Ready?"
A petition to ban the ads generated 70,000 signatures and a wave of vandalism on public transport.
