Despite a serious message, the events were a sea of colour and placards, many of which poked fun at their adult counterparts.
"I'll stop farting if you stop burning coal," one read.
A student at a Sydney event drew cheers for announcing he was "here because we are all from nature and we should all be taking care of it" before playing a clarinet solo.
The stage was set earlier in the week when out of touch Prime Minister Scott Morrison slammed the intended action, saying Australia needed "more learning in schools and less activism". Morrison is clearly incapable of learning.
But the comments only seem to have emboldened the students, as just a few of their signs show.