The 40-year-old put up the photo of his son Brooklyn, 16, steadying the bike as three-year-old Harper grips tightly onto the handles.
Beckham wrote in the caption on Instagram: "Look at my big girl. Day One - No stabilizers."
Although Brooklyn seems to be helping Harper along the grass, she looks pretty steady for a bike with no stabilisers - especially on her first day.
Fans commented on how cute Harper was, with one even writing: "He is legit husband goals".
Beckham is also father to Romeo, 12, and Cruz, 10, with his wife Victoria Beckham.
Being the only girl and the youngest in the family, it seems like Harper is very much looked after by her older brothers.
Beckham posted another photo of her earlier this month playing dress up with his hair. Now THAT is cute.