I'm 24w4d and I can see the baby moving. This weekend I was laying out and you could see my belly popping up when my baby was kicking. Now I can't make out limbs, but you can see movement.
I'm 25 weeks and 4 days and I've been able to see mine move for about a week now. But not every time I feel it. I think it depends alot on your prepregnancy size to be honest. I was 107lbs before getting pregnant and I've gained 10lbs so far
I didn't start seeing my daughter move from the outside till about 28 weeks. But every baby is different due to size and weight. So I would say either between 25-30 weeks