wearing yukata

I wan to ask if we put our beloning inside the sleve of our yukata, will it drop easily because the sleve are not sew together

Some people, let's say when they stroll from their "ryokan" (traditional Japanese inn) in a hot spring town to baths outside their own accommodation, might put a coin purse with some small change in it in the sleeve. The weight keeps it inside the sleeve, without letting it fall out "too easily."

But the sleeve should not be considered like a handbag, you don't want to put anything more than a coin purse or something relatively lightweight and small :)