Ha Long Bay – Cat Ba Archipelago: what UNESCO inscribed in 2023

The short answer

The World Heritage property a visitor hears called "Ha Long Bay" has, since 2023, been "Ha Long Bay – Cat Ba Archipelago". At its extended 45th session that year, the World Heritage Committee approved a significant boundary modification of Ha Long Bay to include the Cat Ba Archipelago, on natural criteria (vii) and (viii).[1] Cat Ba National Park dates the decision to 16 September 2023 in Riyadh.[5]

The decision lists what the property now includes: the existing Ha Long Bay World Heritage site, most of Cat Ba National Park, the Cat Ba World Biosphere Reserve, Cat Ba's marine protected areas and the Long Châu island group, all surrounded by a buffer zone.[1] So Cat Ba is not a separate site next to Ha Long Bay. It is part of the same property, but on the other side of a provincial line: the park describes the property as lying in Quảng Ninh province and Hải Phòng city.[5]

What the 2023 decision says the property is

The Committee's provisional statement describes the property as one of the most important areas in the world for tower karst (fenglin) and peak-cluster karst (fengcong), limestone terrain "flooded by the sea", with towers, notches and caves. Under criterion (vii) it says Cat Ba "adds a new dimension": the largest island in the region, a high island with a wild, hard-to-reach interior of forested peaks, hidden lakes and labyrinthine inlets. Under criterion (viii) it describes the transition from land cone karst to sea-modified tower karst, with the landscape's evolution well advanced in Ha Long Bay and less advanced on Cat Ba.[1]

The same decision gives the property's protection history.[1] UNESCO recognised Ha Long Bay in 1994 and 2000, and the Cat Ba Archipelago as a World Biosphere Reserve in 2004. Nationally, Ha Long Bay became a National Scenic Site in 1962 and a Special National Monument in 2009; Cat Ba became a National Park in 1986, a Marine Protected Area in 2003 and a Special National Monument in 2012. IUCN had recommended adding Cat Ba as early as 2013.[1]

The Thăng Long – Hà Nội Heritage Conservation Centre, which publishes short pages on Vietnam's World Heritage sites, gives the two earlier dates in full: 17 December 1994, at the Committee's 18th session in Thailand, for aesthetic value, and 2 December 2000, in Cairns, for geology and geomorphology.[11] Cat Ba National Park dates the biosphere reserve to 2 December 2004.[7]

Why the figures disagree

Official pages give very different sizes, and they are not measuring the same thing.

• The Thăng Long centre's page describes an inscribed area of 434 km² with 775 islands, a triangle between Đầu Gỗ island, Ba Hầm lake and Cống Tây island.[11] That is the Ha Long Bay property before 2023.
• The Ha Long Bay management board's introduction gives 1,553 km² and 1,969 islands, 980 of them named.[8] That is the bay as a whole, not the inscribed area. The Thăng Long centre's page gives the same totals but says 989 islands are named and 980 unnamed, so even the count of named islands differs.[11]
• Cat Ba National Park's 2026 article gives the extended property as 65,650 hectares with 1,133 limestone islands, and calls it Vietnam's first inter-provincial natural World Heritage site.[6]
• The park's heritage page gives the nominated Cát Bà land area as about 13,000 hectares, surrounded by 20,000 hectares of coastal waters, and the biosphere reserve as 26,300 hectares.[5]

XTOUR could not open UNESCO's own property page (whc.unesco.org/en/list/672 refused the connection on 11 October 2026), so it cannot check any of these against UNESCO's official area. It does not publish one figure as the size of the property.

Lan Hạ Bay and Cat Ba

The Committee's decision does not use the name Lan Hạ Bay.[1] Cat Ba National Park's page places it inside the Cát Bà Archipelago, describing Cát Bà island and the hundreds of small islands around it "on Lan Hạ Bay (Cát Bà Archipelago)" as forming, with nearby Ha Long Bay, the coastal karst landscape that was nominated.[5] XTOUR has not read a boundary map and does not say which parts of Lan Hạ Bay are inside the inscribed area. XTOUR's Hạ Long destination does not include Lan Hạ Bay: the park places the bay in the Cát Bà Archipelago, and its homepage places Cát Bà National Park in Hải Phòng city, not Quảng Ninh.[7][5]

Two provinces, two boards

The 2023 decision named two managers: the Ha Long Bay Management Board for the bay, and a Cat Ba Archipelago Natural Heritage Management Board drawn mainly from the staff of Cat Ba National Park, the biosphere reserve and the Cat Ba bays board, with "systematic coordination" between them. It also tied management to the plans of Quảng Ninh province and Hải Phòng city.[1]

The names have moved since. The Quảng Ninh board's website now calls it the Ban Quản lý di sản thế giới vịnh Hạ Long – Yên Tử, the World Heritage Management Board of Ha Long Bay and Yên Tử, with an address on Lê Thánh Tông street in Hồng Gai ward, Quảng Ninh.[9] Its introduction page says the Ha Long Bay Management Board was founded on 9 December 1995, and that on 10 November 2025 it was merged with the Bái Tử Long National Park board and the province's relics and landscapes board into the new board, under Decision 4166/QĐ-UBND of 1 November 2025.[10] Cat Ba National Park gives its address as Đặc khu Cát Hải, Hải Phòng, a "special zone", while the title of a bay-tourism regulation linked from its homepage still names huyện Cát Hải, Cát Hải district.[7][6] XTOUR has not read the document that created the special zone. The 2025 province mergers and place names explains why addresses like these changed.

What the Committee has asked since

Each year since the extension, the Committee has returned to the same two themes: joint management, and development.

• 2024 (46 COM 7B.67, New Delhi). The Committee said Vietnam's report gave limited information on Cat Ba, asked for an integrated management approach and a coordination mechanism between Quảng Ninh and Hải Phòng, expressed concern that development projects along the coast of Ha Long City had been approved and implemented without clarity on whether their impacts on the property had been properly assessed, and requested a strategic environmental assessment, a zoning map and a joint UNESCO/IUCN monitoring mission.[2]
• 2025 (47 COM 7B.16). The Committee regretted a late report, asked Vietnam to speed up an integrated management body, and noted "with utmost concern" that tourism and infrastructure development on the Ha Long Bay coast and on Cat Ba Island was continuing without a strategic assessment. It asked that the Cat Ba Central Bay tourism project not proceed until its impact had been assessed, and warned that continuing might lead to the property facing potential danger. The monitoring mission visited in March 2025.[3]
• 2026 (48 COM 7B.74, Busan). The Committee welcomed a new 2025 coordination regulation between the two provinces but reported the mission's view that the scale and pace of tourism and urban development around the property were of serious concern, already affecting visual integrity, coastal landscapes and ecosystems. It asked for impact assessments of the Amatina, Central Bay and Domino projects and the Lạch Huyện international seaport, for the joint "Management Board of the Ha Long Bay – Cat Ba Archipelago World Heritage property" to be made operational, and for Cat Ba National Park to be extended to the property's boundaries. Vietnam's next report is due by 1 December 2027.[4]

XTOUR's reading of the three decisions is that the 2023 extension created one property on paper and that, as of 2026, UNESCO still treats its management as divided.

What XTOUR does not know

XTOUR does not know the property's official area, its exact boundary, which Lan Hạ Bay waters lie inside it, or how the joint management board is constituted today. The routes the Quảng Ninh board sells are set out in Ha Long Bay's routes as the management board states them; this page gives no route, duration, price or permit. Vietnam's World Heritage sites lists what XTOUR can source for the country's other properties. For the country, see Vietnam.