The popular Blue Lagoon in Pembrokeshire has closed earlier than usual this autumn to protect a thriving seal population.
It is not uncommon for the lagoon, in Abereiddy, to be filled with seals and their pups this time of year but they have arrived early this year.
The closure by National Trust Cymru, which runs until November, aims to stop them being disturbed.
Large stretches of the Pembrokeshire coast are popular places for breeding Atlantic grey seals which have their pups on the secluded beaches.
Increasing numbers of grey seals breeding in and around the lagoon, coupled with the Blue Lagoon’s high visitor numbers and its sheltered nature means there is a high potential for disturbance to seals, the trust said.
The Blue Lagoon and surrounding beaches are perfect places for seals to rest on land and digest a recent meal, socialise, and feed their young.
It is expected to re-open on 4 November but that will be subject to seal breeding activity at that time.
Three weeks ago, the National Trust closed Mwnt Beach in southern Ceredigion, to protect the seals and their pups.
Mark Underhill, National Trust Cymru’s countryside manager for Pembrokeshire, said there are two species of seal that can be found in Britain; the common seal and the grey seal.
"Only grey seals occur regularly in Pembrokeshire where they are present all year around," he said.
"About half the world’s population of grey seal breed on our coastline and the total number in west Wales, mostly Pembrokeshire, is estimated to be about 5,000, with some 1,400 pups being born each year.
"The breeding season is vital for our seal colonies here in Pembrokeshire and we ask that visitors do not access the Blue Lagoon and that they follow the guidelines laid out by the Seal Alliance and Pembrokeshire Marine Code when on the coastal path."
If a seal is spotted in distress or alone, people should never approach the pup, the trust said.
To raise any concerns about seals or seal pups, you can contact conservation group 'Welsh Marine Life Rescue' by calling 01646 692943.
Want a quick and expert briefing on the biggest news stories? Listen to our latest podcasts to find out What You Need To Know…