Do Thanh Nhan, who dressed as the snake-haired goddess Medusa, said it took a month and a half to prepare his outfit, which cost him VND8 million (US$316).
"I'm thrilled that people are gathering around to take pictures with me," he said.
Costume designer Trang Nee also joined the festivities, donning a self-designed costume that was not based on any particular character.
Two South Korean tourists portrayed the "No Face" character, a dark spirit with a white mask, from Japanese folklore.
They filmed the moment and shared it on social media.
Just 1.4 kilometers from Nguyen Hue, Bui Vien Street, a lively hub of bars and clubs, was equally bustling with crowds attending the "Night of the Souls" event.
Bars and pubs were decorated with Halloween themes to attract tourists, although celebrations have been scaled back this year due to economic difficulties.
"We started decorating the bar with a Halloween theme two weeks ago. This year, things are simpler and less extravagant than in previous years," said a bar owner.
Hong Van and Uyen Phuong (R) from HCMC's District 1 took inspiration for their costumes from the horror film "Carrie".
"It’s our first time here, and the atmosphere is fantastic," said Phuong.
"I took my children to Hang Ma for Halloween celebration and they dressed as No-Face character," said Hong, 26.