Penarth Marina has lost its Blue Flag status in this year's Wales Coast Awards.
It was the last remaining site in the Vale of Glamorgan to retain the prestigious worldwide status, which recognises excellent water quality and facilities.
The privately-owned marina had been recognised since 2021.
Six beaches across the Vale secured the 'Seaside Award', a UK-only scheme which recognises "clean, attractive and well-managed" stretches of the coast.
They include Southerndown, which was stripped of its own Blue Flag status in 2023 because of concerns over its toilet facilities.
Five locations - the Cold Knap, Col-huw in Llantwit Major, Jackson's Bay, Penarth beach and Whitmore Bay - retained their Seaside Award status from last year.
Last year, Dunraven Bay was given an 'excellent' grade for bathing water quality along with the Knap in Barry and Col-huw while Penarth, Jackson's Bay and Whitmore Bay were deemed 'good'.
This year, 21 beaches and marinas were awarded Blue Flags - down from 24 last year - while fifteen sites secured the Seaside Award, up from 12 in 2024.
13 sites retained the Green Coast Award, recognising excellent water quality and unspoiled environmental areas.
Owen Derbyshire, chief executive of Keep Wales Tidy, said: "Most people are familiar with the Blue Flag and Seaside Awards – but it’s just as important that we recognise the wild, unspoilt beaches that stretch along so much of the Welsh coast. "
"The Green Coast Award signifies the highest standards of water quality, environmental education, and site management. These are the sweeping coastlines that define Wales on the world stage – and it’s right that we celebrate these extraordinary places."
Keep Wales Tidy says the annual awards play a vital role in protecting the marine environment - and signfify that a beach or marina meets and maintains the highest environmental standards and achieves tough water quality targets.
Deputy First Minister, Huw Irranca Davies, added: "Wales boasts some of Europe's finest beaches and water quality, and the global recognition of our coastline is a true reflection of the dedication and hard work of so many people...I commend the dedication to preserving our pristine coastal environments."
"As we celebrate in this achievement, let us also heed the call to protect and preserve our coastal treasures. Let's ensure that we leave nothing but footprints, allowing these breathtaking spaces to be enjoyed for many generations to come."
Vale of Glamorgan Council has been approached for a comment.

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