The city approved the measure following a proposal from the Hanoi Department of Culture, Sports and Tourism, according to an announcement on August 25.
The department will work with relevant agencies to implement the policy and develop criteria for free admission to city-managed attractions on major national and Hanoi events in the future.
This year's National Day holiday will give civil servants and public employees five consecutive days off from August 29 to September 2. The official public holidays are September 1 and 2, with the August 31 working day moved to August 22.
For private-sector workers, employers may provide September 2 and either September 1 or September 3 as the two-day National Day holiday, depending on operational requirements.
Ahead of the holiday, Hanoi has asked local authorities, tourism businesses and service providers to strengthen safety measures and improve services for residents and visitors.
Authorities have been asked to coordinate security, healthcare and traffic measures at major tourist sites, including plans to manage visitor flows and prevent overcrowding and congestion.
The city will step up inspections of tourism services, requiring businesses to display and follow listed prices and act against overcharging or harassment of visitors.
Tourist attractions have been asked to provide sufficient staff to assist visitors, maintain environmental and food safety standards and operate hotlines for complaints and enquiries.
Hanoi will also hold cultural and arts programmes and exhibitions to mark the 81st anniversary of the August Revolution and National Day.
Events are planned across several areas, including Hoan Kiem Ward and Hoa Lac, Dan Phuong, Minh Chau, Phuc Son, Bat Trang and Dai Xuyen communes.
At Hoa Lo Prison Relic, a special exhibition titled Tam son, chi thep is scheduled to run from August 19 to September 5.
The free admission and cultural programmes are aimed at serving residents and visitors while promoting Hanoi's historical and cultural heritage.