The 30-year-old activist, who gave birth to her first child in March 2014, posed with Belle at the Celtic Manor in Wales, where she said they were taking their first family holiday.
Katie tweeted excitedly on May 16 that she was 'excited and packing' before updating followers with a picture of their stay.
She wrote: 'Thanks for all the tweets! Wales is lovely! Belle is enjoying her holiday trying to roll over on the grass in the shade!'
The family then headed to Cardiff bay after their stay in the South wales resort.
Katie has previously spoken out about how having Belle has made her life complete, adding: 'To have my own life saved in hospital and then to be there giving life to this precious little person, I thought, "This is what it's all about."'
In 2008, Katie's ex-boyfriend arranged for sulphuric acid to be thrown in her face whilst she was walking down the street. As a result, Piper has to undergo over 100 operations to rebuild her face and try to restore sight in her eye.