Merthyr Tydfil is valley country with lakes that are built for fishing and walking rather than swimming, and one large reservoir where dogs aren’t allowed at all. We couldn’t verify a single place in the borough where a dog may swim, so this is a guide to the best lakeside walks, plus the one spot to avoid altogether.
1. Cyfarthfa Park Lake – Merthyr Tydfil
Address: Cyfarthfa Park, Merthyr Tydfil CF47 8RE
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The lake sits in the grounds of Cyfarthfa Castle, in 160 acres of parkland with gardens, play areas and a model railway. It’s run as an angling water by Merthyr Tydfil Angling Association, fishable from the roadside between pegs 1 and 40, and is described as very popular with dog walkers. We found nothing about swimming either way, so if you’re casting a line yourself, please watch for dogs near the water, and if you’re walking a dog, watch for anglers.
2. Parc Taf Bargoed – Trelewis and Treharris
Address: Trelewis, Treharris, Merthyr Tydfil CF46 6RD
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This Green Flag park was reclaimed from old colliery land, with two lakes built into the valley and the Taff Bargoed river allowed to flow naturally again after its old culvert was removed. The council calls it a hidden gem for walking, cycling and fishing. We couldn’t find any official word on dogs or on swimming, so treat it as a walk and read any signs at the park.
Pontsticill Reservoir: no swimming, and no dogs at all
This one is clear-cut, so we’re putting it plainly. Pontsticill Reservoir, in the Taf Fechan valley south of the Brecon Beacons, is a working water supply managed under Bannau Brycheiniog National Park Authority’s Reservoir Passport Scheme. The scheme’s own passport booklet says that, apart from unforeseen capsizes or essential training, “deliberate immersion activities and swimming are forbidden.” Dลตr Cymru Welsh Water, which owns the reservoirs, “does not permit dogs to be brought onto the reservoir sites” at all, because they supply drinking water. So this isn’t a place for a dog walk by the water, let alone a swim – keep both of you well away.
If a proper swim is the plan
For a genuine dog swim, neighbouring Brecknockshire (Breconshire) has some of the best water in Wales, and there’s a UK dog swimming guide for further afield. Neighbouring Blaenau Gwent is in a similar position to Merthyr Tydfil, with lakeside walks but no verified swim spot either.
Around fishing lakes and busy paths, good manners matter, and a Merthyr Tydfil dog trainer can help with recall near water. If you’re considering everyday extras, Calmshops has Calmdogs 8-in-1 multivitamin chews; ask your vet whether your dog needs them. Local vets are listed under best vets in Merthyr Tydfil, and the rest of our local guides are on dog services in Merthyr Tydfil.
Frequently Asked Questions
Can my dog swim at Cyfarthfa Park Lake?
We found nothing confirming swimming either way. It’s an angling lake run by Merthyr Tydfil Angling Association and is popular with dog walkers, so take care near anglers and check for any signs at the park.
Can dogs swim at Parc Taf Bargoed?
We couldn’t find any official dog or swimming information for this park. It has two lakes and a restored river, so treat it as a walk unless you see signs saying otherwise.
Can my dog swim at Pontsticill Reservoir?
No. Swimming is forbidden under the Reservoir Passport Scheme, and Welsh Water doesn’t permit dogs onto the reservoir sites at all, since they’re a drinking water supply.
Where’s the nearest proper swim for a dog?
Neighbouring Brecknockshire (Breconshire) has some of the best verified dog swimming water in Wales. Our UK dog swimming guide covers more options further afield.
Written by Georgiana & Figo.
