Divers and environmental groups are intensifying opposition to the government's Land Bridge project, warning the megaproject could threaten fragile marine ecosystems and damage the globally renowned diving industry.
Digitalay, a marine conservation network, recently launched the "Divers Against Land Bridge" campaign to rally public support against the project, which would connect the Gulf of Thailand and the Andaman Sea through a transport corridor and two deep-sea ports.
Through photos and underwater videos shared on social media, the campaign aims to highlight marine biodiversity and raise awareness among people who may never have the opportunity to witness the country's underwater ecosystems first-hand.
Nat Sumanateme, a professional marine wildlife photographer and member of Digitalay, said the country's marine environment had gradually recovered in recent years following stricter enforcement against illegal, unreported and unregulated (IUU) fishing.
However, Mr Nat warned the Land Bridge project, backed by the Bhumjaithai Party-led government, posed a threat to the sustainability of southern marine ecosystems.
"We still do not know the exact shipping routes because the government has not released detailed information," he said.
"But regardless of the route, the project will inevitably affect marine ecosystems, especially world-class diving sites such as Richelieu Rock."
Speaking to the Bangkok Post, Mr Nat said construction of deep-sea ports would generate massive sedimentation, one of the leading causes of coral reef degradation.
He added marine ecosystems are interconnected, meaning damage in one area could spread to surrounding habitats.
He cited the 2010 coral bleaching crisis in Mu Koh Surin National Park, noting recovery over the past 16 years had depended partly on coral larvae carried by ocean currents from Myanmar waters.
"That natural recovery may no longer occur if there is heavy vessel traffic through sensitive marine routes," he said, warning that underwater noise, ship propellers and possible oil contamination could disrupt coral migration and marine life reproduction.
"The government has never treated natural resources as national capital," he added. "Without transparency, many people will not accept this project."
The Professional Association of Diving Instructors (Padi) says Thailand ranks among the world's top destinations for diving certification, with key sites including Koh Tao, Mu Koh Surin and Koh Lipe.
Napaket Limthanakit, founder of Dive Team Thailand and a master diving instructor, said Koh Tao alone produces 50,000 divers annually and generates 10 billion baht in local revenue.
"Thailand is known as the world's dive school," Ms Napaket said.
She added divers typically spend two to three times more than ordinary tourists due to costs related to diving courses, boats and equipment.
Courses in Koh Tao range from 25,000 to 40,000 baht, while courses in the Andaman Sea can cost up to 100,000 baht.
"If we lose Richelieu Rock, divers will stop coming," she said.
"It is one of the most unique marine habitats in the world, home to rare species such as whale sharks and manta rays."
Ms Napaket said divers, marine experts and public figures would continue campaigning against the project to protect marine resources for future generations.
The ruling Bhumjaithai Party has defended the proposed Land Bridge megaproject, saying the scheme remained at the feasibility study stage and would not proceed if studies found it unviable or if residents opposed it.
In remarks posted on its Facebook page under the headline "Clearing Up the Facts About the Land Bridge", the party said no construction or investment had yet been approved.
The party said the project aimed to position Thailand as a regional logistics hub by reducing maritime transport times, improving national competitiveness, creating jobs and generating long-term economic growth.
It added that a 90-day impact study committee, led by Deputy Prime Minister and Finance Minister Ekniti Nitithanprapas, would evaluate the project.
The party insisted that if studies concluded the project was not economically viable or if local residents rejected it, the scheme will not proceed.
