The owners of the former Aberthaw power station have been granted a High Court injunction against trespassers.
It follows a spate of online videos by 'urban explorers' who managed to enter the coal-fired plant, which was decommissioned in March 2020.
CCR Energy, which brought the site for £8 million in 2022, says the injunction covers land within the construction design and management boundary and runs until March 2027.
Demolition work is currently taking place at the former power station, which has been earmarked for a green energy hub.
But the energy firm stressed it does not affect the nearby section of the Wales Coast Path, which remains open to the public.
A CCR Energy spokesperson said: "This supports our continued commitment to ensuring the highest standards of safety and security on the site while demolition and remediation works continue."
"The injunction will help prevent unauthorised access and trespassers, safeguarding both the public and on-site workforce. Warning notices will be displayed around the boundary to make the restrictions clear."
"The injunction applies exclusively to CCR Energy owned land within the CDM boundary and does not affect the coastal path - which remains open and fully accessible to the public."

CCR Energy is a subisdary of the Cardiff Capital Region, a group of ten local councils in South East Wales, including the Vale of Glamorgan.
They plan to transform the former Aberthaw power plant, which dates back to the early 1960s, into a "cutting-edge" low carbon destination.
A spokesperson added: "Beyond energy, the vision extends to delivering economic regeneration for the region - supporting new, high-value jobs, attracting investment, and fostering a hub for sustainable technologies."
"We remain committed to transparent engagement with local communities and stakeholders throughout the entire redevelopment journey and will continue to provide timely updates as work at Aberthaw progresses."
Earlier this year, it emerged CCR had settled a legal dispute for £5.25 million after the High Court ruled a contract to demolish the power station had been awarded unfairly - with the findings of an independent review due to be published by the end of the year.

Vueling withdraws winter flights to Aicante this winter
Playground in Barry forced to close after fire damages equipment
Campaigners Take Fight for Fairer Pathways in Welsh Women’s Football to Parliament
Vale Councillor Gwyn John Launches His First Novel at Llantwit Major Book Signing
Pink poppy display commences with celebration of life
Former Barry office block converted into new homes for people at risk of homelessness
Welsh Government publishes independent report on Level 4 intervention at Cardiff and Vale UHB
Three CoastSnap stations set to be installed along the Glamorgan Heritage Coast
Daffodil Runner statue installed at Marie Curie Hospice in Penarth
Woman Dies After Incident in Leckwith as Police Investigation Continues
Vale entrepreneur wins national Innovate UK award for sustainable construction technology
Cardiff Airport retains top accessibility rating as regulator reports record demand for assistance
Open Doors event to showcase hidden world of Glamorgan Archives
New details have emerged of a new tree-lined public square that will replace a traffic dominated junction
Dyffryn Gardens’ Edwardian rose garden blooms again after decade-long restoration
Barry’s Own Daniel White to Walk 190 Miles Back to Where His Round Table Story Began
1,300 people attend Flying Start Family Fun Day
Dispersal order put in place to tackle anti-social behaviour
Interim Chief Executive Appointed at Cardiff and Vale University Health Board
Cardiff Theatre Marks 50 Years of Service for Long‑Standing Staff Member