When exactly do the events of Karate Kid III take place?
If I remember correctly, Part II literally picks up where the first one left off at the All-Valley Tournament. And Part III picks up with Daniel and Mr. Miyagi returning to the United States from Okinawa following the events of the second movie. According to Wikipedia, Part III begins in September 1985. So KKIII is what TV Tropes likes to call, a "Present Day Past" story.
https://en.wikipedia.org/wiki/The_Karate_Kid_Part_III
The timeline doesn't make sense!!
https://www.reddit.com/r/cobrakai/comments/9bp2lp/the_timeline_doesnt_make_sense/
How Old Daniel Is In Each Karate Kid Movie (& Cobra Kai)
https://screenrant.com/karate-kid-daniel-age-how-old-cobra-kai/