The Halong-Yen Tu World Heritage Management Board said unauthorised operators have been offering tours using unregistered vessels or boats not licensed to carry passengers.
Passengers are typically picked up at sites such as Halong 1 Market, Hon Gai pier, areas near Vincom Halong, the former Bai Chay ferry terminal and Cai Xa Cong wharf before heading offshore.
Many tours are arranged via social media by individuals, posing risks to public order and waterway safety, especially in poor weather.
Waterway police have launched inspections to identify violations, with strict penalties for operators lacking proper certification and checks on crew alcohol and drug use.
Authorities are also requiring vessel owners and captains to commit to compliance, avoid operating without permits and meet safety standards.
On March 15, the management board urged coastal wards to discourage residents, particularly fishing boat owners, from running illegal tours and called for tighter controls at inland wharves.
