Phất Cờ Island is located in Bái Tử Long Bay, about 1.5km from the Việt – Mỹ tourist area boat port. Seen from the shore, the island resembles a green arc standing guard over the vast sea – home to a “farm” growing carrageenan seaweed.
Phất Cờ Island – Home to a Floating Sea Farm in Bái Tử Long Bay
Phất Cờ Cave
The island belongs to the port area of Hamlet 2, Hạ Long Commune, Vân Đồn District, Quảng Ninh Province. During the French occupation of the mining region, the French named the island ile du Marquis (the marquis). On July 13, 1968, the Ministry of Home Affairs revised and standardized the name ile du Marquis as Phất Cờ Island and this has remained the island’s official name to this day.
Phất Cờ Island. Photo: Quảng Ninh Newspaper.
Phất Cờ Island is actually a rocky island like many other rocky islands in Hạ Long Bay and Bái Tử Long Bay, but it is distinctive in having Phất Cờ Cave, one of the largest caves in Bái Tử Long Bay. In front of the cave is a golden sandy beach about 50m long, suitable for swimming and relaxation.
Cave entrance. Photo: Quảng Ninh Newspaper.
Phất Cờ Cave resembles an egg, with the entrance located around the middle of the egg. From the sandy beach, visitors climb up the high stone steps to reach the cave entrance. The cave is very spacious, with many stalactites resembling natural works of art. In the dark recesses, water drips from the cave ceiling, creating a damp atmosphere.
A natural waterhole. Photo: Quảng Ninh Newspaper.
Phất Cờ Cave. Photo: Quảng Ninh Newspaper.
Entering the cave through its dark passages, visitors are amazed by a powerful beam of light—the natural light shining through a cave opening like a giant funnel mouth. Thanks to this light source, many plant species have grown inside the cave, creating an eye-catching carpet of lush greenery.
Striking stalactites. Photo: Quảng Ninh Newspaper.
Wind blows down from above and in through the cave openings, keeping the middle of the cave dry. From the cave floor up to the southern entrance is a wonderful vantage point for viewing a corner of the vast, wave-filled Bái Tử Long Bay. Looking out from this cave entrance is Miếu Islet, which contains Soi Nhụ Cave, a settlement site of ancient Vietnamese people dating back 10,000 years.
The cave has many chambers. Photo: Quảng Ninh Newspaper.
Floating Sea Farm
In addition to the cave, Phất Cờ Island also has a floating farm cultivating carrageenan seaweed on the sea surface in the waters around the rocky island. This is the first successful carrageenan seaweed cultivation model in the coastal waters of Quảng Ninh Province.
Photo: quangninh.gov.vn.
The floating farm was established in February 2021 and officially began operating after three months. It was built with HDPE panels and blocks, creating a beautiful, sturdy and convenient space.
Successful carrageenan seaweed cultivation. Photo: VnExpress.
The floating farm covers around 10ha on the sea around Phất Cờ Island. Visitors can walk around to see the carrageenan seaweed cultivation rafts or paddle boats to visit the “floating gardens” where carrageenan seaweed is suspended.
Seaweed is cultivated intensively. Photo: Quảng Ninh Newspaper.
Visitors can also tour the seed bank and drying yards for the seaweed products floating in the middle of the sea, which are made entirely from large HDPE panels. Here, visitors can experience harvesting and processing the seaweed, drying it, and enjoying specialty dishes made from carrageenan seaweed.
Carrageenan seaweed farm. Photo: Quảng Ninh Newspaper.
Carrageenan seaweed at Phất Cờ Island reaches maturity after just 2 to 2.5 months of cultivation. This is also the period when the seaweed meets the criteria for use as an ingredient in food, cosmetics, medicinal products…
Carrageenan seaweed is used for many purposes. Photo: Quảng Ninh Newspaper.
Up to three carrageenan seaweed crops can be cultivated each year, with yields reaching 70-100 tons/ha/year. With the current seaweed price at 2,500-3,000 đồng/kg fresh, revenue can reach around 200 million đồng/ha, helping transform the economy and improve the quality of life of carrageenan seaweed farmers.
