Media playback is unsupported on your device Media caption Facebook group Bioluminescent Plankton Watch Wales has more than 6,000 members

"Every splash, every jump, made the sea just light up. It won't be an experience we forget easily."

Photographers and nature lovers have been watching bioluminescent plankton glowing off the Welsh coast.

Bioluminescence describes the light that some living creatures, such as fireflies and jellyfish, emit from their cells.

Photographer Kris Williams captured the first sighting in Wales this year in Beaumaris, Anglesey on 24 June.

Image copyright Kris Williams Image caption Photographer Kris Williams captured this image off Penmon Point, Anglesey on 26 June

He has been photographing the phenomenon in Wales since 2016.

The first confirmed sighting of the year off the south Wales coast was on 28 June by another photographer Lee McGrath, near Nash Point in the Vale of Glamorgan.

Facebook group Bioluminescent Plankton Watch Wales has more than 6,000 members who share their experiences and photographs after observing the natural phenomenon off the Welsh coast.

Image copyright Kathryn Donovan Image caption Kathryn Donovan and her family are keen bioluminescent plankton hunters

Kathryn Donovan, from Cardiff, has made night-time trips to Aberavon Beach in Port Talbot on three occasions and described it as a "family adventure" with her husband, parents and children aged four and seven.

She said: "As soon as we moved away from the street lights, we could see this beautiful bright blue spark across the sea...

"We went and splashed in the sea with my boys. It was magical.

"They still talk about it now - a night out under the stars with hot chocolate and swimming in the bright blue sea. Every splash, every jump made the sea just light up. It won't be an experience we forget easily."

Image copyright Rhys Martin Image caption Rhys Martin took this photo of Aberavon Beach on 8 July

Image copyright Daz Martin Photography Image caption Darren Martin said the "waves appeared as though they were filled with electricity" off Averavon Beach, Port Talbot, on 6 August 2018

Micki Payne, from Llantwit Major, Vale of Glamorgan also visited Aberavon Beach with her daughters aged four and seven. She said: "It was so exciting walking down to the beach at night.

"We felt safe as there were so many people around and a buzz of excitement.

"As [the waves] rolled out, the sand was left sparkling, the girls thought it was magical. They wrote their names in the sparkly sand and drew pictures."

Image copyright Lee McGrath Image caption Lee McGrath captured this display off Aberavon

Mandy Brunton drove from Nuneaton, Warwickshire, with her daughter and dog, and they slept in their car overnight in order to view the plankton at Penmon Point on Anglesey.

"We were thrilled," she said. "A very epic short adventure which I'm sure we will do again."

Rhys Martin, from Crynant, Neath Port Talbot has become hooked on bioluminescent plankton hunting since he was enchanted by an image on Facebook: "I thought 'wow, that's definitely a bucket list item'. I thought if there was a chance I could see it I would."

Image copyright Thomas Winstone Image caption Thomas Winstone shot this on Caswell Bay, Gower, after dozens of visits

He now heads out to spots including Aberavon Beach, Oxwich and Three Cliffs bays on the Gower most evenings.

"I'd been out nine or 10 times before saw it for the first time," he said.

"If you're splashing around in the water, words can't describe - it is mind-blowing, absolutely amazing. There's nothing else I've seen like it, like electricity on water."

Image copyright Emma-Louise Image caption Emma-Louise Williams took this shot off Aberavon Beach, Port Talbot

Thomas Winstone finally witnessed the phenomenon at Caswell Bay, Gower, after "dozens of visits". He said a highlight was "seeing it shine as I swam through it, it glowing as it dripped off me and then seeing the fish lighting up blue as they swam away".

Pete Ryan, one of the administrators of the Facebook group, said one hunter had been making trips from London to try and see the phenomenon: "[He] got to see it at his third attempt... try, then try again."

But he warned the coast could be dangerous and discouraged hunters from swimming in the dark.