It is actually easier to learn bouldering at their age and size and many kids do both top rope and bouldering. Agree with the PP about learning from a trained instructor on how to fall properly. Most youth climbing teams train kids in both. Because it is possible to fall and land in an awkward way, it is riskier than top rope but some find it more challenging/fun.

They should do a bouldering intro class at the minimum so they know how to fall and learn proper etiquette - not just for politeness but safety too. I see too many kids running under people on the wall! Additionally, you should probably take the class so you know how to keep an eye on them. Plus, it is great strength training. As someone who is afraid of heights I much prefer bouldering. My college age daughter is a huge climber and sees no problem with letting them boulder now. The thing that scares me the most with climbing is doing lead climbing out in the real outdoors and making a mistake. Or free climbing .

My 2 elementary kids have been doing top rope rock climbing with instructors for 1 year. They are just average. At the indoor rock climbing center like sportsrock, I have been seeing more people doing bouldering by themselves or with friends. May I ask if doing bouldering need an instructor or not for kids or I just let them play around by themselves? It seems bouldering need a lot of strength or muscle, is that more easier to get hurt or better to wait till my kids ate older till age 12/13? They are 7 and 10 now.