The girls enjoyed a thrilling day out at the Staffordshire theme park for an event hosted by Mind Charity, minus band mates Rochelle Humes and Una Healy.
But while Mollie and Vanessa took on daring roller-coaster rides, pregnant Frankie was left to play the role of bag holder!
Frankie, who is expecting a baby boy with fiancé Wayne Bridge, took to Twitter to comment on the day trip. She said: "Alton Towers fun. I was bag holder obviously! @mindcharity."
The 24-year-old cosied up to an enormous Sonic The Hedgehog figure, and unveiled the return of her trademark short hair!
It was only last month that Frankie showed off her drastic new look after opting for long hair extensions, but it seems her tried-and-tested short cropped style is back.
Mollie, who wore a navy dress and black ankle boots, certainly measured up to Sonic as she put her foot on top of his famous red running shoes.
Meanwhile Vanessa, who wore a denim dungaree dress, was all smiles as she donned a large pair of sunglasses.
Mollie captioned the photo: "Franollie hit Alton Towers #Mind #Summertime."
The girls weren't alone though, as Vanessa was joined by her stylist boyfriend Gary Salter, and Mollie bought along her US music producer boyfriend Jordan Omley.
Commenting on the snap, Vanessa said: "Fun times!! @molliethesaturdays @instagazman and Jordan and @francescasandford even though she's not present in the pic lol."
Vanessa added: "Great time @altontowers with the gang today! All thanks to @MindCharity."
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