Nha Trang Bay has a total area of 249.65 km², with 211.85 km² of sea surface area (adjacent to the mainland) and 37.8 km² of islands within the bay. The bay is located along the coastal arc of Nha Trang city, bounded by Ke Ga Cape to Cu Hin Cape, and includes 19 islands of various sizes. The largest island is Hon Tre, covering an area of 3.265 hectares, while the smallest is Hon Do, with an area of approximately 0.3 hectares.

In terms of ecological value, Nha Trang Bay is home to a rare natural model of a bay system found worldwide. Most of the rare and typical ecosystems of tropical seas are concentrated here, such as wetlands, coral reefs, mangrove forests, seagrass beds, estuarine ecosystems, island marine ecosystems, and coastal sand ecosystems. Together, these create a vast community of organisms that contribute to the bay's magnificent beauty.

Regarding biodiversity, Nha Trang Bay holds significant potential compared to many other coastal regions of Vietnam, with over 350 species of hard corals forming reefs, ranking it as one of the most biodiverse in terms of coral reef species. The bay is also home to 6 species of mangrove plants, 7 species of seagrass, 222 species of reef fish, and many other benthic animals of high economic value, such as lobsters and sea cucumbers.

Nha Trang Bay is a water area that brings benefits not only to the residents of Nha Trang City but also to the entire Khanh Hoa Province. It serves as a national center for entertainment and tourism.

Recognizing its importance, on December 20, 2000, the Prime Minister approved the pilot project for the Hon Mun Marine Protected Area with the goal of protecting typical marine biodiversity of international significance, enhancing livelihoods for local communities, and working with the community to effectively manage the marine protected area, serving as a model for other marine protected areas to be established in Vietnam.

In 2001, the People's Committee of Khanh Hoa Province issued a decision to establish the management board for the Hon Mun Marine Protected Area (later renamed the Nha Trang Bay Marine Protected Area Management Board) to organize the implementation of the Hon Mun project.

In 2012, the People's Committee of Khanh Hoa Province issued a decision to establish the Nha Trang Bay Management Board with the function of assisting the People's Committee of Nha Trang City in managing the exploitation of the bay's values while protecting and preserving the scenic beauty and biodiversity. The board also serves as the coordinating body with provincial authorities to implement integrated management of Nha Trang Bay.

In 2003, Nha Trang Bay was accepted as the 29th member of the Most Beautiful Bays in the World Club.

With the characteristic features of Nha Trang Bay, which hosts most of the typical marine ecosystems as mentioned above, each ecosystem is home to distinct communities of organisms that are interconnected with their surroundings, helping to maintain biodiversity.

These characteristic ecosystems also serve as "breeding grounds," "spawning areas," and nurseries for the young of various aquatic species. They provide food and habitats for many marine species, contributing to the conservation of biodiversity and the ecological balance of Nha Trang Bay.

Additionally, the ecosystems in the bay also offer economic benefits such as coastal fishing and aquaculture.

Mr. Dam Hai Van, Head of the Nha Trang Bay Management Board, stated that in recent years, the management, conservation and promotion of the values of Nha Trang Bay have achieved certain results, contributing to the development of tourism in Nha Trang city and Khanh Hoa province. The number of tourists visiting Nha Trang to explore the bay has been steadily increasing, and the revenue from tourism has contributed to the economic development of the city, bringing significant benefits to the local community. Additionally, Nha Trang Bay has also become a place for scientists to study and research the ocean, while students have the opportunity to experience and explore the marine world.

Nha Trang Bay is Vietnam's first marine protected area and a national scenic site.

However, recently, the coral reefs in the Hon Mun area, Nha Trang Bay, have shown signs of degradation. According to the opinions of experts, scientists, the report from the Nha Trang Bay Management Board, the People's Committee of Nha Trang City, and the feedback from participants in the initial meeting, it is clear that the decline of most of the coral reefs in the Hon Mun Marine Protected Area is a process influenced by the accumulation of factors over many years, including both objective and subjective causes.

Among the objective causes are the impacts of climate change, the effects of Typhoon Damrey in 2017, and Typhoon No. 9 in 2021 (without ocean acidification phenomena). The subjective causes are related to human activities affecting the Nha Trang Bay ecosystem in general and the coral reefs in the Hon Mun Marine Protected Area in particular, which have not been addressed in a timely manner. There are still illegal fishing activities, as well as waste discharge from tourism and aquaculture activities.

In light of the above situation, preserving and restoring the coral reefs in Nha Trang Bay, including the Hon Mun marine area, is one of the key tasks, both urgent and long-term, for Khanh Hoa Province in general and Nha Trang City in particular. This is especially significant as the province implements Resolution No. 09-NQ/TW dated January 28, 2022, from the Politburo on building and developing Khanh Hoa Province by 2030, with a vision toward 2045. According to this, the development of Khanh Hoa must be based on the effective and sustainable use of marine resources, environmental protection, and adaptation to climate change.

In line with the directives from the Party Civil Affairs Committee of the People's Committee of Khanh Hoa Province, as outlined in Official Letter No. 228 on June 22, 2022, regarding the implementation of the conclusion from the Standing Committee of the Provincial Party at Announcement No. 347 on June 21, 2022, on deploying both short-term and long-term measures to address the coral reef degradation in Hon Mun and Nha Trang Bay, the People's Committee of Khanh Hoa Province issued Decision No. 3028 on November 7, 2022, to approve the master plan for restoring Nha Trang Bay by 2030.

After more than 2 years of implementing the plan, many positive results have been achieved; the political system at all levels, sectors and the support of the people have been mobilized to work together in protecting Nha Trang Bay in a sustainable and long-term manner.

According to Mr. Dam Hai Van, since July 1, 2022, the Nha Trang Bay Management Board has announced the temporary suspension of swimming, diving, and other tourism activities in the waters around Hon Mun Island until further notice.

The management board has only arranged temporary diving activities at the Northeast of Hon Rơm Island, a location with suitable natural conditions, limited to a specific number of guests, and only available to registered professional sports diving organizations or individuals. Participants must have an international diving certification. The Nha Trang Bay Inter-Departmental Inspection Team and the patrol team under the management board regularly patrol and inspect the bay to address administrative violations.

Mr. Huynh Trung Thao, in charge of the patrol team at the Nha Trang Bay Management Board, stated that to prevent illegal fishing activities in Nha Trang Bay, especially in the marine protected area, the patrol team, consisting of 15 members, operates in two shifts, 24/7, out at sea.

The good news is that thanks to increased awareness campaigns, most of the local people now understand the benefits of protecting the biodiversity values in Nha Trang Bay. As a result, illegal fishing activities in the bay have gradually decreased, especially the large-scale fishing vessels that no longer operate within Nha Trang Bay.

Not only has illegal fishing been prevented, but the Nha Trang Bay Management Board also regularly monitors the coral reef ecosystems or any incidents that may impact the marine environment, such as coral bleaching caused by climate change, as advised by the National Oceanic and Atmospheric Administration (NOAA).

Mr. Nguyen Duc Minh Tan, Deputy Head of the Conservation Department, Nha Trang Bay Management Board, said: "Over the past time, we have regularly dived weekly to collect crown-of-thorns starfish and gather debris from the seafloor at Hon Mun and Hon Chong to protect the marine environment of Nha Trang Bay. The management board also coordinates with the Institute of Oceanography and the Vietnam-Russia Tropical Center – Coastal Branch to survey the status of coral reefs at Hon Mun, Hon Chong, and other areas within and around Nha Trang Bay in order to propose effective restoration management solutions".

At the same time, the Nha Trang Bay Management Board has also developed plans and implemented projects to restore coral reefs, mangrove forests, and replenish fishery resources. Specifically, tasks have been proposed such as the scientific task at the local level: "Creating a nursery to provide coral reef species for the restoration and regeneration of coral reef ecosystems in Nha Trang Bay"; and the provincial-level scientific task: "Experimenting with artificial reef creation associated with marine ecotourism and recreational fishing at the western area of Hon Mun, Nha Trang Bay", which has been approved by the Provincial People's Committee as part of the scientific and technological tasks for the 2024 plan.

In addition, the Nha Trang Bay Management Board has issued and maintained the implementation of a notice prohibiting the use of single-use plastic products at Nha Trang tourist pier. This regulation has gained strong support from the community, and it has been highly successful, with businesses at the pier and Hon Mun now using environmentally friendly alternatives instead of single-use plastic products in their operations.

The Nha Trang Bay Management Board has also mobilized social resources to replenish fishery resources in the bay, plant mangrove forests in Dam Bay since 2004, and plant mangrove trees in the Tac River basin. These activities aim to accelerate the restoration of ecosystems in the bay and increase the area of mangrove forests within and around the bay, as part of the tasks outlined in the "Green transformation, green growth project of Nha Trang city for the period 2024-2030". At the same time, the community is being encouraged to join efforts in planting trees and forest regeneration, as well as protecting the environment, which will contribute to mitigating the impacts of natural disasters and climate change.

According to Mr. Dam Hai Van, with the implementation of comprehensive tasks and solutions in the overall plan for restoring Nha Trang Bay, significant progress has been made.

Specifically, monitoring results show that the amount of waste at Hon Mun has decreased significantly compared to previous years, due to the requirement that residents and tourists not bring single-use plastic products through the Nha Trang Tourist Pier before boarding canoes to visit the bay. The coral reef at Hon Mun is showing slow recovery after past events, while the coral reef at Hon Chong is developing well, with high coverage and many valuable fish species returning to inhabit and reproduce there.

In the strictly protected zone of Hon Mun, sea turtles have been spotted, indicating that the environment of Nha Trang Bay is improving.

Sea turtles can be considered an indicator species, symbolizing the health and cleanliness of the marine environment.

However, in order to sustainably conserve and enhance the value of the marine protected area in Nha Trang Bay, it is essential to build sustainable livelihoods for the local communities who depend on aquaculture and fishing in the bay.

In this regard, the Head of the Nha Trang Bay Management Board further mentioned that the overall restoration plan for Nha Trang Bay also outlines sustainable livelihood solutions for the communities living and working in aquaculture and fishing on the bay. The People's Committee of Khanh Hoa province has assigned the Khanh Hoa Women's Union to take the lead, in collaboration with the Nha Trang Bay Management Board, to develop a proposal and project outline titled "Promoting dialogue and cooperation between the community, private sector, and government agencies in coral reef conservation and sustainable development of the Hon Mun marine area, Nha Trang Bay, Khanh Hoa province" for submission to the Small Grants Program of the Global Environment Facility (GEF SGP).

The project was approved by the People's Committee of Khanh Hoa Province to receive funding and is being implemented from July 2023 to December 2024. The project has included several rounds of feedback collection and training for the people of Bich Dam village on community livelihood development. Additionally, study tours have been organized to learn from the model of coral reef protection and ecosystem conservation with community participation, linked to eco-tourism at Hon Yen (Phu Yen Province).

Along with this, the project has organized dialogue sessions and workshops to propose a sustainable eco-tourism development model with community participation at the Bich Dam residential area. Additionally, a consultation workshop on the zoning of functional areas of the Nha Trang Bay Marine Protected Area was held. At the end of the first phase of the project, the Women's Union of Khanh Hoa Province, in collaboration with relevant parties, proposed the implementation of a community-based tourism development model linked to environmental protection and coral reef conservation at Bich Dam residential area, Vinh Nguyen ward.

The good news for the local community is that the People's Committee of Nha Trang City has recently approved a proposal for the development of green, sustainable community-based tourism at Bich Dam, contributing to creating a new tourism product, providing sustainable livelihoods for local people, and supporting the conservation and development of marine biodiversity, maintaining public security, environmental hygiene, and protecting maritime sovereignty.