Fanart Ponyo: 

Ponyo and Sosuke are wearing modern Vietnamese ao dai

Fanart Howl's Moving Castle:

Sophie and Howl in traditional costumes of the early Le Dynasty

The Áo giao lĩnh (交领) was a traditional cross-collared robe worn by Vietnamese 

Fanart Spirited Away: Chihiro and Haku are wearing Giao Linh

Kiki's delivery service

The Wind Raise

Naoko is wearing ao dai which is the national dress of the Vietnamese.