Phu Yen General Hospital said the incidents occurred along the Phuoc Tan-Bai Nga coastal road in Hoa Xuan Commune, where the visitors were attacked while heading to a sightseeing destination.
The hospital received the five patients over April 28-29 with monkey bites to various parts of the body.
Three of the victims suffered multiple wounds over large areas of the body, raising concerns over infection and rabies exposure, hospital officials said.
Doctors cleaned and sutured the wounds, applied dressings and administered anti-rabies serum.
The remaining two patients sustained less severe injuries and were also assessed for rabies exposure before receiving preventive treatment.
No serious complications or deaths had been recorded as of April 30, the hospital said.
Local authorities in Hoa Xuan Commune have erected warning signs advising visitors not to approach or feed wild monkeys to prevent further incidents.