The Ya Ya celebration is a celebration of the origins of the culture of Phuket.
The celebration will take place at the Central Festival just outside Phuket Town. There will be a fashion show, a cultural performance and more - from 4pm onwards.
There will be the Peranakan Museum in Phuket Town which will allow you to explore the culture and the history of the Baba-Nyonya people.
For a greater explanation of the cultures and of the festival - visit here.
I missed was the Phuket Old Town Festival.