Llwyn-on Reservoir: A Tranquil Jewel in the Brecon Beacons

Discover serene waters, scenic walks, and rich wildlife at Llwyn-on Reservoir, the largest reservoir in the Taf Fawr valley nestled in the Brecon Beacons.

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Llwyn-on Reservoir

Llwyn-on Reservoir, situated near Merthyr Tydfil within the Brecon Beacons National Park, is the largest reservoir in the Taf Fawr valley. Built in the 1920s, it offers scenic walking trails, abundant wildlife, and excellent fishing opportunities. Its peaceful waters and surrounding woodlands create a serene environment ideal for nature lovers and outdoor enthusiasts alike.

A brief summary to Llwyn-on Reservoir

Merthyr Tydfil, GB
Duration: 1 to 3 hours
Free
Outdoor
Mobile reception: 4 out of 5

Local tips

Visit during dry spells to see the ancient Pont ar Daf bridge emerge from the water—a rare and photogenic sight.
Bring fishing gear and purchase a day ticket if you want to fish for rainbow and wild brown trout.
Use the Garwnant Visitor Centre as a base for amenities like toilets, refreshments, and outdoor play areas.
Wear sturdy walking shoes for the 5 km circular trail, which includes some uneven surfaces and gentle inclines.
Respect wildlife habitats and follow Leave-No-Trace principles to help preserve the reservoir’s natural beauty.

Getting There

Car

Driving from Merthyr Tydfil to Llwyn-on Reservoir takes about 15-20 minutes via local roads. Free parking is available near the Garwnant Visitor Centre. Note that road access is seasonal and can be narrow in places.
Bus

Local bus services connect Merthyr Tydfil with stops near the A470 road by the reservoir. Bus journeys typically take 30-40 minutes. Check current timetables as frequency varies and walking from the stop to the reservoir involves 1-2 km on uneven terrain.
Walking

For active visitors, a 5 km circular walking route around the reservoir offers moderate terrain with some gentle inclines. The path is well-maintained but includes uneven surfaces, suitable for most fitness levels but not wheelchair accessible.

Llwyn-on Reservoir location weather suitability

Any Weather
Rain / Wet Weather
Clear Skies
Mild Temperatures
Windy Conditions

Discover more about Llwyn-on Reservoir

Historical Roots and Engineering Feat

Llwyn-on Reservoir was constructed in the early 20th century, with work beginning in 1911 and completion in the 1920s. It was part of a strategic effort authorized by the Cardiff Corporation Act of 1884 to increase water supply to Cardiff. The reservoir was built on the River Taf Fawr, approximately 4 miles upstream from Merthyr Tydfil, with an earthen dam designed to hold 670 million imperial gallons of water. The construction involved significant infrastructure, including a contractors' village and railway connections, which were later dismantled by 1928. Since 1973, the reservoir has been managed by Welsh Water, ensuring its role as a key water resource while preserving its natural surroundings.

Natural Setting and Wildlife

Nestled within the Brecon Beacons National Park, Llwyn-on Reservoir straddles the Merthyr Tydfil and Rhondda Cynon Taf areas. The reservoir covers around 150 acres, making it the largest in the Taf Fawr valley. Its waters are fed by the Afon Taf Fawr and tributaries such as Nant Gwinau, Nant Car, and Garwnant. The surrounding landscape features a mix of tranquil conifer plantations and open water views. This habitat supports diverse wildlife including otters, great crested grebes, goldeneye ducks, goosanders, and coots, benefiting from the clean, well-managed water environment.

Recreational Activities and Visitor Experience

Visitors to Llwyn-on Reservoir can enjoy a variety of outdoor activities. The main attraction is a roughly 5 km circular walk around the reservoir, featuring a mix of flat and gently sloping terrain suitable for most fitness levels. The path offers continuous scenic views of the water and the Brecon Beacons hills, passing through mossy conifer forests and open areas. Picnic spots with benches and tables are available, along with a food trailer at times. Fishing is popular here, with the reservoir well-stocked with rainbow trout and wild brown trout, and permits available for fly, spinning, and worm fishing. The nearby Garwnant Visitor Centre provides amenities including toilets, refreshments, and outdoor play areas.

Unique Features and Seasonal Highlights

One of the reservoir’s distinctive features is the Pont ar Daf bridge, an ancient structure that occasionally emerges from the water during dry spells, creating a captivating and photogenic spectacle. The reservoir’s water levels fluctuate seasonally, enhancing the variety of visual experiences throughout the year. The area’s clean water and natural setting also make it a favored spot for wildlife observation and photography. The forest surrounding the reservoir was planted soon after its construction to prevent soil erosion, adding to the verdant and peaceful atmosphere.

Conservation and Management

Llwyn-on Reservoir is carefully managed to balance its role as a water supply with environmental conservation. The surrounding woodlands and water quality support a thriving ecosystem, and efforts are made to maintain compensation water flows to sustain the river's health downstream. The site is part of a protected landscape within the Brecon Beacons National Park, emphasizing sustainable access and low-impact recreation. Visitors are encouraged to respect the natural environment and adhere to guidelines to preserve the reservoir’s tranquility and ecological value.

Accessibility and Surrounding Attractions

The reservoir is easily accessible from Merthyr Tydfil and Cardiff, with parking available near the Garwnant Visitor Centre. The walking trails are well-maintained, with some sections suitable for families and casual walkers. The area also offers opportunities for dog walking and nature escapes, making it a versatile destination for day trips or weekend getaways. Nearby attractions in the Brecon Beacons provide additional cultural and outdoor experiences, enhancing the appeal of Llwyn-on Reservoir as a peaceful retreat within South Wales.

Historic Wales’ oldest hotel blending timeless charm with modern comforts near Brecon Beacons National Park.

Unmissable attractions to see

Cadair Fawr

2.9 km

Accessible mountain views across South Wales' rolling landscape, perfect for all abilities.

Castell Morlais 'Morlais Castle'

4.9 km

Explore the evocative ruins of 13th-century Castell Morlais, perched above Merthyr Tydfil with panoramic views and rich medieval history.

Brecon Mountain Railway

5.7 km

Experience the magic of steam through the breathtaking Brecon Beacons on a historic heritage railway journey.

Twyn Mwyalchod

5.8 km

A steep yet rewarding trig point summit offering panoramic ridge views and poignant memorials in the heart of the Brecon Beacons.

Cyfarthfa Castle Museum and Art Gallery

5.8 km

Explore the grand industrial heritage and art treasures of Cyfarthfa Castle, a majestic 19th-century ironmaster’s mansion set in expansive parkland.

Penderyn Brecon Beacons Distillery - Visitor Centre and Shop

6.7 km

Discover the home of Welsh whisky in the Brecon Beacons – tour the original Penderyn Distillery, see the Faraday still, and taste award-winning single malts.

Penderyn Brecon Beacons Distillery - Visitor Centre and Shop

St Tydfil Shopping Centre

7.2 km

Merthyr Tydfil’s premier shopping centre offering a modern, accessible retail experience with over 50 shops and ample parking in the town heart.

Bannau Brycheiniog National Park (Brecon Beacons)

7.3 km

Explore Wales’ breathtaking Bannau Brycheiniog National Park, where majestic peaks, cascading waterfalls, and rich heritage await every adventurer.

Bannau Brycheiniog National Park (Brecon Beacons)

Porth yr Ogof

7.9 km

Explore Wales’ largest cave entrance, a thrilling limestone labyrinth carved by the Afon Mellte in the heart of Brecon Beacons National Park.

Sgwd Yr Eira Waterfall

8.0 km

Walk behind the stunning 50-foot curtain of water at Sgwd yr Eira, the enchanting Waterfall of Snow in Wales’ Brecon Beacons.

National Trust - Brecon Beacons

8.1 km

Explore Pen y Fan and the Brecon Beacons from Pont ar Daf, where nature, adventure, and modern facilities meet in Wales’ iconic mountain park.

Four Waterfalls Walk

8.1 km

Discover the enchanting Four Waterfalls Walk, a scenic 9 km trail through ancient woodland and cascading falls in Wales’ Brecon Beacons National Park.

Fan Fawr

8.2 km

Fan Fawr: A majestic peak in Wales’ Brecon Beacons, blending stunning glacial landscapes with rich geology and timeless Welsh legends.

Pen-y-Fan walk carpark

8.2 km

Primary access point for hiking Pen y Fan, South Wales’ highest peak, nestled in the scenic Brecon Beacons National Park.

Sgwd Clun-Gwyn Waterfall

8.3 km

Discover the cascading beauty of Sgwd Clun-Gwyn, a serene multi-step waterfall nestled in the lush woodlands of South Wales’ Brecon Beacons.

Essential places to dine

Aberglais Inn

4.3 km

Cozy pub and restaurant in Merthyr Tydfil offering hearty British classics, vegan and gluten-free options, with a warm, friendly atmosphere.

Mango House Restaurant

4.7 km

Experience authentic Indian cuisine with warm hospitality in the heart of Merthyr Tydfil’s Cefn-coed-y-cymmer.

Red Cow Inn

5.1 km

A charming traditional Welsh pub in Pontsticill offering hearty home-cooked meals, award-winning ales, and a warm, welcoming atmosphere.

The Pantyscallog Inn

6.5 km

A beloved steakhouse in Pant, Merthyr Tydfil, known for hearty portions, friendly service, and a warm, welcoming atmosphere.

The Red Lion Inn, Penderyn

7.1 km

A cozy Welsh gastropub blending traditional charm, local flavors, and legendary roasts in the scenic village of Penderyn.

Rhydycar Harvester

7.8 km

Casual family dining with classic British flavors and welcoming amenities in Merthyr Tydfil’s Rhydycar Leisure Park.

Pentrebach House Table Table

9.8 km

Classic British pub dining with family-friendly charm and hearty meals in the heart of Merthyr Tydfil.

The Farmers Arms

10.9 km

Historic farmhouse pub in Rhymney offering scratch-cooked Welsh cuisine, a full bar, and a warm, welcoming atmosphere for all occasions.

The Tai’r Bull Inn

14.1 km

A cosy Welsh country pub and B&B offering hearty fare, real ales, and warm hospitality in the heart of Brecon Beacons National Park.

The White Hart

15.0 km

Traditional Welsh inn in Talybont-on-Usk offering hearty British fare, local ales, and warm hospitality near the Brecon Beacons.

Travellers Rest Inn

15.2 km

Cozy countryside inn with hearty meals and warm hospitality near the scenic Brecon Beacons.

Carnivore By The Mine

15.4 km

A cozy meat-lover’s haven in Neath, blending hearty dishes with heartfelt mining heritage and warm local charm.

Penycae Inn Ltd

16.3 km

Cozy gastropub in the heart of South Wales offering fine Welsh cuisine, scenic mountain views, and a unique family-friendly atmosphere.

The Red Lion

16.6 km

A historic Welsh village pub blending centuries-old charm with warm hospitality and local brews in the heart of Llangynidr.

Gorkha & Khukuri

16.6 km

Savor authentic Nepalese cuisine in a serene Brecon setting, where tradition and flavor unite at Gorkha & Khukuri.

Markets, malls and hidden boutiques

Izzy Roo's

Explore Brecon with confidence, staying connected at Get Connected—the mobile shop for all your tech needs in the heart of the town.

The Vapour Den

16.9 km

Explore Brecon’s vibrant vaporizing culture at The Vapour Den, your friendly local shop for expert advice and quality vaporizers.

Premier

17.0 km

Your friendly, convenient stop for groceries and essentials in the heart of Brecon, open early to late every day.

Essential bars & hidden hideouts

The Star Inn

15.0 km

A cozy and characterful pub with quality food and a sunny beer garden in the heart of Talybont-on-Usk, perfect for walkers and families alike.

Royal Oak

15.6 km

Cozy Welsh pub in Pencelli offering traditional hospitality and local ales amidst the scenic Brecon Beacons.

Coach & Horses

15.9 km

Historic canal-side pub and inn in Llangynidr offering hearty Welsh fare, cozy rooms, and a warm, welcoming atmosphere.

Drovers Arms

16.5 km

A welcoming Welsh village pub blending historic charm with hearty fare and friendly hospitality in the heart of Llanfaes, Brecon.

The Three Horseshoes Inn

16.7 km

A cosy Welsh village pub blending traditional charm with refined British cuisine and a warm, welcoming atmosphere.

hop in beer and gin

16.8 km

Discover Brecon’s quirky bar with top-quality craft beers, artisanal gins, and delicious tapas in a cozy, historic setting.

The Rorkes Drift

16.9 km

Historic Welsh pub in Brecon offering local ales, lively music, and a warm atmosphere inspired by the legendary Rorke’s Drift battle.

Markets Tavern

17.0 km

Traditional Welsh pub and welcoming hotel in Brecon offering hearty food, cozy rooms, and authentic local charm on Free Street.

The Sarah Siddons

17.0 km

Experience authentic Welsh hospitality with local ales and lively atmosphere at The Sarah Siddons, Brecon’s beloved town centre pub.

The Lounge Bar & Cafe

17.1 km

Brecon’s pioneering bar with a modern twist, offering signature cocktails, live music, and a welcoming atmosphere in the town centre.

The New Inn

17.3 km

A cozy, affordable pub and backpackers’ haven in Bwlch, offering hearty food, friendly service, and a welcoming base for exploring the Brecon Beacons.

Lakeside Bar

19.5 km

Relax lakeside at this friendly pub within Brecon’s scenic caravan park, perfect for unwinding after exploring the Brecon Beacons.

The Red Lion Llangorse

20.1 km

A welcoming Welsh gastropub in Llangorse offering seasonal local dishes, real fires, and a cozy atmosphere near the Brecon Beacons.

Jolly Colliers

21.6 km

A cozy, friendly pub in Llanelly Hill offering hearty British fare and rustic tapas in a charming countryside setting.

The Pwllgloyw Arms

21.7 km

A cozy mountain pub in Powys offering hearty Welsh fare, local ales, and a warm, welcoming atmosphere year-round.

Nightclubs & after hour spots

The Kirkhouse Nightclub (Koolers)

6.9 km

Experience the vibrant and friendly nightlife of Merthyr Tydfil at The Kirkhouse Nightclub, known locally as Koolers.

Pure Bar & Nightclub Ltd

7.1 km

A lively nightclub and cocktail bar in Merthyr Tydfil offering vibrant music, crafted drinks, and late-night entertainment in South Wales.

Northcote Conservative Club

16.9 km

Discover the lively ambiance of Northcote Conservative Club, Brecon's premier destination for nightlife, music, and local culture.

Brecon Jazz Club (Muse Arts Centre)

17.0 km

Discover the heart of jazz in Brecon at the Brecon Jazz Club, where live music and a vibrant atmosphere collide for an unforgettable night.

BRECON JAZZ

17.0 km

Experience the soulful sounds of Brecon Jazz, an intimate venue celebrating the rich heritage of jazz music in the heart of Wales.

Brecon Working Mens Club

17.0 km

Experience authentic Welsh hospitality at Brecon Working Mens Club, where locals gather for drinks and camaraderie in a charming setting.

Squares Night club

20.8 km

Experience Porth’s vibrant nightlife at Squares Nightclub, where music, dance, and unforgettable evenings come alive every weekend.

The Top Club

21.7 km

Experience Blaengarw’s vibrant nightlife at The Top Club, where electrifying entertainment meets community spirit in the heart of South Wales.

Eclipse Nightclub

24.6 km

Experience Pontypridd’s vibrant midweek nightlife at Eclipse Nightclub, where music, dancing, and community come alive every Wednesday night.

The Arch Bar & Nightclub

29.4 km

A lively Neath hotspot blending nightclub energy, live music, pub charm, and Thai cuisine in one vibrant venue.

Jimmy's Bar

32.7 km

Experience the vibrant nightlife and live music scene at Jimmy's Bar, Port Talbot’s lively local hotspot with a welcoming atmosphere.

Mojos

38.4 km

Discover the vibrant nightlife of Newport at Mojos, the go-to cocktail bar for creative drinks and nightly karaoke excitement.

Vibez

38.4 km

Experience Newport’s vibrant nightlife at Vibez Superclub, where pounding bass and late-night energy create unforgettable weekend parties.

Hush Newport

38.5 km

Experience the vibrant Saturday nightlife at Hush Newport, Baneswell’s hotspot for music, dancing, and late-night fun in the heart of Newport.

Stow Hill Rooms

38.6 km

A stylish Art Deco nightclub and function venue in the heart of Newport, blending vibrant nightlife with versatile event spaces.

Your Ultimate Free Travel Guide

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Llwyn-on Reservoir: A Tranquil Jewel in the Brecon Beacons

A brief summary to Llwyn-on Reservoir

Local tips

For the on-the-go comforts that matter to you

Getting There

Car

Bus

Walking

Llwyn-on Reservoir location weather suitability

Unlock the Best of Llwyn-on Reservoir

Buy tickets

Book tours with entry

Book tours without entry

Discover more about Llwyn-on Reservoir

Historical Roots and Engineering Feat

Natural Setting and Wildlife

Recreational Activities and Visitor Experience

Unique Features and Seasonal Highlights

Conservation and Management

Accessibility and Surrounding Attractions

Iconic landmarks you can’t miss

YHA Brecon Beacons

Brecon Canal Basin

Brecon Barracks

The Royal Welsh Regimental Museum

Brynich Lock

Cefn Llechid

Y Gaer Museum, Art Gallery & Library

Brynich Aqueduct

Duke of Wellington Monument

Brecon Town Tours - guided history walks

Gate Gallery & Glassworks

The Promenade

Visit Brecon

Craig-y-Nos Country Park

The Brecon Castle Hotel

Unmissable attractions to see

Cadair Fawr

Castell Morlais 'Morlais Castle'

Brecon Mountain Railway

Twyn Mwyalchod

Cyfarthfa Castle Museum and Art Gallery

Penderyn Brecon Beacons Distillery - Visitor Centre and Shop

St Tydfil Shopping Centre

Bannau Brycheiniog National Park (Brecon Beacons)

Porth yr Ogof

Sgwd Yr Eira Waterfall

National Trust - Brecon Beacons

Four Waterfalls Walk

Fan Fawr

Pen-y-Fan walk carpark

Sgwd Clun-Gwyn Waterfall

Essential places to dine

Aberglais Inn

Mango House Restaurant

Red Cow Inn

The Pantyscallog Inn

The Red Lion Inn, Penderyn

Rhydycar Harvester

Pentrebach House Table Table

The Farmers Arms

The Tai’r Bull Inn

The White Hart

Travellers Rest Inn

Carnivore By The Mine

Penycae Inn Ltd

The Red Lion

Gorkha & Khukuri

Markets, malls and hidden boutiques

Izzy Roo's

Gwent Shopping Centre

The UK Loose Leaf Tea Company Ltd

KM Gifts & Accessories

Hay & Brecon Farmers Brecon

Mind

B&M Home Store with Garden Centre

CERTAS - BRECON

DIXIES CORNER

Beacons Antiques

Kitty Keane's Vintage