A Magaluf 'booze cruise' ad has been banned for linking drinking with sexual success.
It featured women kissing, one drinking from a spirits bottle and a man rubbing his face into a woman's chest.
The Advertising Standards Authority said the suggestive images implied "those attending the event would be sexually successful."
Revellers were also shown holding up signs stating: "I'm behaving badly on Sunset Booze Cruise", "Single as F***" and "I left my boyfriend back in England."
The ASA said: "We considered the ad's emphasis on the large quantities of alcohol offered and the inclusion of the images selected from the image gallery to promote the Booze Cruise event linked alcohol with sexual activity and therefore breached the Code."
Organisers Magaluf Events denied the individuals were under the age of 25 which is against the CAP Code when marketing alcohol.
But the industry watchdog said several looked younger, some of whom were actually shown drinking.
It said: "We considered images of a sexual nature were featured on the event page, such as images showing two people kissing and a man rubbing his face into a woman's chest.
"We also considered the images of attendees holding up signs with the text 'I'm behaving badly on Sunset Booze Cruise', 'Single as F***' and 'I left my boyfriend back in England' were sexually suggestive and implied those attending the event would be sexually successful.
"We considered the ad's emphasis on the large quantities of alcohol offered and the inclusion of the images selected from the image gallery to promote the Booze Cruise event linked alcohol with sexual activity and therefore breached the Code."
Magaluf booze cruises, where Brits abroad are plied with free alcohol and urged to play sexually charged drinking games, are notorious.
Magaluf Council has been reported to be planning a crack down, with authorities eager to issue fines for the drunken behaviour - in the same way as if it happened in bars, restaurants or clubs.
The holiday resort has become a well known destination for young people planning their first trip abroad with friends. The trips were made famous in British comedy, The Inbetweeners Movie.
The ASA upheld three complaints that the ad irresponsibly promoted excessive drinking, those featured appeared to be under the age of 25 and that it linked alcohol with sexual success.
The ASA said the ad "must not appear again in its current form."
They added: "We told Magaluf Events to ensure their future advertising was socially responsible, did not encourage excessive drinking or feature those who appeared to be under 25 years of age drinking alcohol or playing a significant role, and did not link alcohol to sexual activity."
The ad appeared on Magaluf Events' website in December promoting a 'Sunset Booze Cruise', and stated: 'You'll see the mayhem we cause on the Mediterranean is unrivalled anywhere on the planet!'
It offered a three hour unlimited free bar onboard with shots of Sambuca, Apple Sourz and Skittle Vodka, adding: "We promise you will walk on the boat but we'll have you crawling off!'
A table on the website indicated access was allowed with a standard priced ticket - with VIP tickets including an additional bottle of champagne per person.
At the bottom of the web page a collage of 18 photos were displayed as part of the image gallery for previous events, featuring the controversial pictures.
Magaluf Events said they had been diligent in checking identification and they had consent forms from those involved with any promotional work, including those featured on the web page, to state they were over 25.
They explained they would not be looking to change the images as appearing to be over 25 was subjective, and they worked on a factual basis.
But they acknowledged there were issues with elements of their content and images regarding the promotion of sexual activity and alcohol consumption. They added they were willing to "make amendments."
Magaluf is a favourite party destination for British tourists who come to blow off steam and enjoy the cheap alcohol prices on offer.
But bad behaviour over the years, including binge drinking, sex in the streets, fighting and nudity, have given Brits a bad reputation with the Spanish authorities.