Up to about 7 or 8 IME but lots of older kids are into it too. I haven't been in a long time so don't know what the lines ar like now.

I'm going to raise Janis by 2. Assuming the kid has enjoyed playing with Legos, it's fun through about 10 years old. I also haven't been for years, but if it is as I remembered, the lines were nothing like Disneyland. Disneyland has become painful. Especially in summer, and this is coming from someone who went twice a year since the Anaheim park first opened.

It also depends on the particular child. It would be good to know if the 8 or 10 yr old considers "Legos for babies...."

https://www.isitpacked.com/crowd-calendars/
This crowd predictor site appears to list Legoland as well as others.

He is the perfect Legoland visitor.

Thanks all.

Jamie, I'd never seen that site before.

I took my son to Legoland Florida when he was 5. He loved it. We also that year went to Great Wolf Lodge and Disneyland. Legoland was the one he asked to go back to.

My grandson, a seven-year-old LEGO fanatic, will be there one of those days too! He's currently putting together the Millenium Falcon which his other grandma gave him for Christmas.