The Hong Kong-Zhuhai-Macao Bridge: Engineering the World's Longest Bridge-cum-Tunnel Sea Crossing

How the Hong Kong-Zhuhai-Macao Bridge was built: its bridges, artificial islands and undersea tunnel, the 2018 opening and what it changed for travel.

A Silverfox Studios Perspective ON

October 16, 2026

· 5 min read

^{A 55-KILOMETRE SEA CROSSING THAT GAVE HONG KONG AND MACAU THEIR FIRST LAND LINK}

Western section of the Hong Kong-Zhuhai-Macao Bridge crossing the Pearl River Estuary — The western section of the Hong Kong-Zhuhai-Macao Bridge, seen from a ferry leaving Macau. Image: N509FZ (CC BY-SA 4.0), via Wikimedia Commons

The Hong Kong-Zhuhai-Macao Bridge (HZMB) is a road link of about 55 kilometres that crosses the Lingding waters of the Pearl River Estuary, connecting Hong Kong on the eastern side with Zhuhai and Macau on the western side. It opened to traffic at 9am on 24 October 2018. The Hong Kong government describes it as the longest bridge-cum-tunnel sea crossing in the world, and as the first land link between Hong Kong and Macau. The crossing is not a single bridge: its 29.6-kilometre main section combines about 22.9 kilometres of bridge, a 6.7-kilometre immersed tunnel and two artificial islands where the road changes from one to the other. The mix of bridge, islands and tunnel was set by the site: a shipping channel crossed by about 4,000 vessels a day, the height limit around Hong Kong International Airport, and an estuary exposed to typhoons.

^{WHAT IS THE HONG KONG-ZHUHAI-MACAO BRIDGE MADE OF}

Hong Kong-Zhuhai-Macao Bridge over open water — The Hong Kong-Zhuhai-Macao Bridge across the Pearl River Estuary. Image: Pauloleong2002 (CC BY-SA 4.0), via Wikimedia Commons

Macau's Transport Bureau divides the project into three parts: the main bridge-and-tunnel works at sea, the boundary crossing ports in Hong Kong, Zhuhai and Macau, and the link roads in each of the three places. Hong Kong's Highways Department breaks the 55 kilometres down further: the 12-kilometre Hong Kong Link Road, the 29.6-kilometre Main Bridge and the 13.4-kilometre Zhuhai Link Road. The main works were built to a dual three-lane expressway standard with a design speed of 100 kilometres per hour.

The bridge sections include three cable-stayed navigation bridges with main spans of 280 to 460 metres, linked by viaducts with spans of 75 and 110 metres. The towers of the three navigation bridges take three forms, symbolising a Chinese knot, a dolphin and a wind sail; the dolphin tower rises to about 100 metres and weighs 2,600 tonnes. On the Hong Kong side, the Link Road runs as a 9.4-kilometre viaduct, a 1-kilometre tunnel through Scenic Hill and a 1.6-kilometre section at ground level. One 180-metre span was used to avoid a headland at Sha Lo Wan that is of high archaeological value. The Hong Kong Port sits on about 130 hectares of reclaimed land next to the airport, and the roof of its Passenger Clearance Building was assembled from 81 prefabricated modules.

^{WHEN WAS THE BRIDGE BUILT AND HOW LONG DID IT TAKE}

China's State Council approved the feasibility study on 28 October 2009, the Ministry of Transport approved the preliminary design on 31 March 2010, and the Hong Kong-Zhuhai-Macao Bridge Authority was set up in July 2010 to oversee construction, operation and maintenance of the main works. The approved investment for those main works was RMB 48.064 billion. For the project as a whole, the trade journal World Highways reported an original estimate of nearly US$16 billion, with delays adding around US$1.5 billion.

World Highways reports that construction began in December 2009 and that a legal challenge over the bridge's environmental impact caused delays up to 2011. A paper in the Chinese Academy of Engineering's journal Engineering dates the start of construction of the main works to January 2011. The island and tunnel works were delivered under a design-build contract covering survey, design, research and construction, with China Communications Construction Company as lead designer and general contractor. The final closure joint of the tunnel was installed on 2 May 2017, and the works were completed and handed over in February 2018. The opening ceremony was held at the Zhuhai Port passenger clearance building on 23 October 2018, and traffic began at 9am the following morning.

^{WHY PART OF THE CROSSING RUNS UNDER THE SEA}

Eastern tunnel portal of the Hong Kong-Zhuhai-Macao Bridge — The eastern portal of the crossing's immersed tunnel, on one of its two artificial islands. Image: N509FZ (CC BY-SA 4.0), via Wikimedia Commons

The eastern part of the main section is a tunnel because a bridge could not meet two limits at once. The main navigation channel had to stay open for oil tankers of up to 300,000 tonnes, and the structure also had to stay within the height clearance limit set by Hong Kong International Airport. A tunnel meets both conditions: ships pass over it, and nothing stands above the airport's height limit. About 4,000 vessels cross the Lingding Channel each day, and the tunnel lies beneath the Lingding West Fairway and the Tonggu Channel.

The two artificial islands, each about 100,000 square metres, are where the road descends from the bridge into the tunnel and rises again. Builders formed them from 120 steel cylinders, prefabricated in Hong Kong, each 22 metres in diameter and 50 metres high, sunk about 30 metres into the soft seabed. Each island ring was formed from 60 cylinders set side by side, with auxiliary cells connecting them and reaching down into the impermeable ground layer so that the interior could be dewatered. The method reduced the time needed to form the islands to about seven months, and the buildings on the islands were built around the same steel supports.

^{HOW THE UNDERSEA TUNNEL WAS BUILT}

The tunnel is an immersed tube, assembled on the seabed from 33 precast elements and a closure joint. A typical element is 180 metres long, about 38 metres wide and 11.4 metres high, and weighs about 76,000 tonnes. The elements were cast in a purpose-built factory on Guishan Island near Zhuhai, which covered 560,000 square metres and employed a staff of 1,200, and five of them are curved. Inside, the elements carry a six-lane highway, and ENR described the tunnel as the world's longest immersed road tunnel when it named the island and tunnel works its Best Project in the bridge and tunnel category in 2018.

Each element was towed out by a fleet of 12 tugboats and lowered into place, and the 33 elements were installed in 35 operations with no major accidents. The tunnel is buried up to 22 metres below the seabed, on soft soil more than 30 metres thick and in water up to 50 metres deep. To cope with these loads the engineers developed semi-rigid elements, a composite foundation layer and a 'memory bearing' to limit damage from uneven settlement. The joints use water-sealing closure details, and the project reports zero tunnel leakage from the installation of the first element in May 2013. A deployable closure joint cut the marine work needed to complete the tunnel from more than six months to three days.

^{DESIGNING FOR TYPHOONS, EARTHQUAKES AND A 120-YEAR LIFE}

The HZMB has a design life of 120 years. The estuary is exposed to typhoons and monsoons. After Typhoon Haiyan in 2013, the project's hazard design was upgraded, and the site later withstood typhoons Hato and Mangkhut. The bridge is designed for wind speeds of 200 kilometres per hour, and both bridge and tunnel are designed to withstand an earthquake of up to magnitude 8.0.

The works also lie within a protected area for the Chinese white dolphin. On the Hong Kong side, the viaduct uses prestressed precast piers to reduce underwater work, and a floating concrete batching plant was used for the first time in Hong Kong. The Scenic Hill Tunnel was built using four construction methods, including box jacking beneath the Airport Express line so that the railway could keep running safely. The Hong Kong Port uses a district cooling system that, according to the Highways Department, uses 35 per cent less electricity than air-cooled systems.

^{WHAT THE BRIDGE CHANGED FOR TRAVEL BETWEEN HONG KONG, MACAU AND ZHUHAI}

Bus stop at the Hong Kong Port Passenger Clearance Building — The bus stop at the Passenger Clearance Building, Hong Kong Port of the bridge, October 2018. Image: LN9267 (CC BY-SA 4.0), via Wikimedia Commons

Shortly before opening, Hong Kong's Secretary for Transport and Housing, Frank Chan Fan, said the journey from Zhuhai to Hong Kong International Airport would fall from about four hours to about 45 minutes, and from Zhuhai to the Kwai Tsing Container Terminals from three and a half hours to 75 minutes. He added that the western Pearl River Delta would be brought within three hours' drive of Hong Kong. The crossing operates 24 hours a day. It also created a new land boundary crossing between Hong Kong and Guangdong, with the Hong Kong Port on Lantau next to the airport.

Cross-border private car travel over the bridge is managed through quota schemes for Guangdong-Hong Kong and Hong Kong-Macao cars. In July 2023, Hong Kong introduced the Northbound Travel for Hong Kong Vehicles scheme, which lets eligible Hong Kong private cars drive into Guangdong over the bridge without a regular quota. On 18 April 2025, the first day of the Easter holiday, about 6,500 vehicles under the scheme crossed, according to the Hong Kong government. About 6,900 trips had been booked for that day, and more than four-fifths of the vehicles that travelled kept to their reserved time slot. Eligible cars can also use the bridge under the regular quotas and through a park-and-ride scheme at the Macao Port.

^{THE BRIDGE AND HYATT REGENCY HENGQIN}

Hyatt Regency Hengqin, designed by Silverfox Studios — Hyatt Regency Hengqin, Zhuhai, China

Hyatt Regency Hengqin, completed in 2019, the year after the crossing opened, is the hospitality anchor of Lai Sun Creative Culture City on Hengqin Island, within Novotown, with 493 guestrooms and suites and interiors by Silverfox Studios. The hotel is connected to Hong Kong and Macau via the Hong Kong-Zhuhai-Macao Bridge. Its interiors use material warmth and Asian craft, with vertical timber slats, woven linen, rattan and pale veined stone. Views toward the Hengqin hills and toward Macau, one of the three places the bridge connects, shaped the design.