Llwyn-onn Reservoir: A Tranquil Water Haven in the Brecon Beacons
Discover the tranquil expanse of Llwyn-onn Reservoir, a historic water haven nestled in the scenic Brecon Beacons National Park near Merthyr Tydfil.
Llwyn-onn Reservoir, the largest in the Taf Fawr valley, is a serene reservoir nestled within the Brecon Beacons National Park near Merthyr Tydfil. Built in the 1920s, it spans 150 acres and offers peaceful walking trails, abundant wildlife, and scenic views framed by surrounding hills and forests. It is a favored spot for fishing, picnics, and nature lovers seeking a tranquil escape in South Wales.
A brief summary to Llwyn-on Reservoir
- Merthyr Tydfil, GB
- Duration: 1 to 3 hours
- Free
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Outdoor
- Mobile reception: 4 out of 5
Local tips
- Bring suitable footwear for walking on mixed surfaces including compacted paths and occasional loose gravel.
- Fishing permits are required for anglers; check local regulations before planning your visit.
- Picnic areas are available but consider bringing your own food and water, as facilities are limited.
- The reservoir is dog-friendly with ample space for off-leash walking in designated areas.
- Visit during different seasons to experience varied wildlife activity and changing landscapes.
For the on-the-go comforts that matter to you
- Restrooms
- Food Options
- Seating Areas
- Picnic Areas
- Trash Bins
- Information Boards
Getting There
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Car
Driving from Cardiff to Llwyn-onn Reservoir takes approximately 40 to 50 minutes via the A470. Parking is available near the reservoir, but spaces can fill during weekends and holidays. No parking fees apply.
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Bus
Local bus services connect Merthyr Tydfil to areas near the reservoir, with travel times ranging from 20 to 40 minutes depending on the route. Service frequency varies, so check schedules in advance. Walking from the nearest stop involves moderate terrain.
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Walking
For visitors staying in Merthyr Tydfil, walking to the reservoir is possible but requires about 1.5 to 2 hours over mixed terrain including minor inclines. Suitable for fit walkers and dog owners.
Llwyn-on Reservoir location weather suitability
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Any Weather
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Rain / Wet Weather
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Clear Skies
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Mild Temperatures
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Cold Weather
Discover more about Llwyn-on Reservoir
Historic Origins and Engineering Feat
Llwyn-onn Reservoir was constructed in the early 20th century, with work commencing in 1911 and completion in the 1920s. It was developed following the Cardiff Corporation Waterworks Act of 1884 to enhance Cardiff's water supply. Positioned on the River Taf Fawr, the reservoir was designed to hold approximately 670 million imperial gallons of water. The dam construction involved significant engineering efforts, including excavations down to solid rock and the establishment of a contractors' village and railway connections to support the build. Since 1973, Welsh Water has managed the reservoir, ensuring its role in regional water supply and environmental stewardship.Natural Setting within the Brecon Beacons
Situated within the expansive Brecon Beacons National Park, Llwyn-onn Reservoir straddles the Merthyr Tydfil and Rhondda Cynon Taf boundaries. The reservoir is surrounded by lush conifer plantations planted shortly after its completion to prevent soil erosion into the water. The area offers a blend of tranquil forested zones and open water vistas, with the A470 trunk road running along its eastern shore. Its scenic environment supports diverse wildlife, including otters, great crested grebes, goldeneye ducks, goosanders, and coots, which thrive in the clean waters and protected habitat.Recreational Opportunities and Visitor Experience
Covering 150 acres, Llwyn-onn Reservoir is popular for walking, fishing, and picnicking. The reservoir features well-maintained trails with a grade 2 walking route that combines compacted surfaces and gentle gradients, suitable for most visitors including seniors. Picnic areas with tables and benches are scattered around the site, complemented by a food trailer offering refreshments. Anglers favor the reservoir for its stocked rainbow trout and wild brown trout populations, supporting fly, spinner, and worm fishing. The peaceful ambiance and natural beauty make it a perfect spot for dog walking and nature observation.Ecological Importance and Conservation
The reservoir and its surroundings are carefully managed to maintain water quality and protect local ecosystems. The conifer plantations play a vital role in reducing sediment runoff, while the reservoir itself provides a habitat for various bird species and aquatic life. Conservation efforts ensure that the area remains a sustainable natural resource within the national park, balancing human use with wildlife preservation.Access and Surrounding Attractions
Llwyn-onn Reservoir is easily accessible by car, approximately 40 minutes from Cardiff, with parking available nearby. The site serves as a gateway to the broader Brecon Beacons National Park, offering visitors opportunities to explore additional trails, viewpoints, and cultural heritage sites. The reservoir's proximity to Merthyr Tydfil makes it a convenient day trip destination for those seeking outdoor relaxation and scenic beauty in South Wales.Atmosphere and Seasonal Highlights
The reservoir exudes a tranquil and reflective atmosphere, enhanced by the gentle sounds of water and birdsong. Seasonal changes bring varied experiences—from vibrant autumn foliage and crisp winter walks to blossoming spring greenery and warm summer picnics. Visitors often remark on the peacefulness and restorative quality of the environment, making Llwyn-onn a cherished spot for mindfulness and nature connection.Iconic landmarks you can’t miss
YHA Brecon Beacons
11.0 km
Rustic farmhouse hostel offering clean, cozy accommodation and a warm communal atmosphere in the heart of Brecon Beacons National Park.
Brecon Canal Basin
16.7 km
Breathe in the beauty of Brecon Canal Basin, a serene escape in Wales perfect for leisurely walks, local cuisine, and outdoor adventures amidst stunning landscapes.
Brecon Barracks
16.7 km
Historic military hub in Brecon, home to the Royal Welsh Regiment and its museum, set within the stunning Brecon Beacons National Park.
The Royal Welsh Regimental Museum
16.8 km
Explore the Royal Welsh Regimental Museum in Brecon, where Wales' military history comes alive through captivating exhibits and rich heritage.
Brynich Lock
16.8 km
Experience the serene beauty of Brynich Lock, a tranquil spot along the Brecon & Monmouthshire Canal, perfect for nature lovers and peaceful escapes.
Cefn Llechid
16.8 km
Explore Cefn Llechid in Brecon Beacons National Park for breathtaking views, outdoor adventures, and a rich tapestry of history.
Y Gaer Museum, Art Gallery & Library
16.9 km
Explore Y Gaer Museum, Art Gallery & Library in Brecon for an enriching experience of local history, art, and literature in a cultural landmark.
Brynich Aqueduct
16.9 km
Historic stone aqueduct carrying the Monmouthshire and Brecon Canal over the River Usk, showcasing early 19th-century engineering and scenic beauty.
Duke of Wellington Monument
16.9 km
Historic bronze statue honoring the Duke of Wellington, a commanding presence in Brecon’s town centre and a testament to local artistry and British heritage.
Brecon Town Tours - guided history walks
16.9 km
Experience the rich history of Brecon with guided tours that unveil the town's hidden gems and captivating stories in the heart of the Brecon Beacons.
Gate Gallery & Glassworks
17.0 km
Discover the artistic beauty of handmade glassware at Gate Gallery & Glassworks in Brecon, where craftsmanship meets creativity.
The Promenade
17.0 km
Discover tranquility and natural beauty at The Promenade in Brecon, a perfect park to unwind and enjoy the stunning Welsh landscape.
Visit Brecon
17.0 km
Explore the beauty of Brecon, a quaint Welsh town that serves as the gateway to the stunning Brecon Beacons National Park.
Craig-y-Nos Country Park
17.0 km
Explore the enchanting landscapes and rich history of Craig-y-Nos Country Park, a perfect retreat in the Brecon Beacons for nature lovers and adventure seekers.
The Brecon Castle Hotel
17.1 km
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.
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.
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
13.7 km
Explore Izzy Roo's in Tredegar for unique gifts and local crafts, capturing the essence of the region's charm and creativity.
Gwent Shopping Centre
13.7 km
A vibrant retail hub in Tredegar offering diverse shops, convenient hours, and a welcoming community atmosphere.
The UK Loose Leaf Tea Company Ltd
16.0 km
Discover ethically sourced, premium loose leaf teas and sustainable brewing essentials at The UK Loose Leaf Tea Company Ltd in Brecon.
KM Gifts & Accessories
16.2 km
Discover quality gifts, stylish accessories, and friendly service at KM Gifts & Accessories in the heart of Ebbw Vale.
Hay & Brecon Farmers Brecon
16.2 km
Experience the best of local Welsh produce at Hay & Brecon Farmers Brecon, where freshness and quality meet a warm community spirit.
Mind
16.3 km
Explore unique finds and support mental health initiatives at Mind Charity Shop in Brecon, where every purchase makes a difference.
B&M Home Store with Garden Centre
16.4 km
Affordable shopping meets gardening passion at Brecon’s versatile B&M Home Store with Garden Centre.
CERTAS - BRECON
16.6 km
Discover convenience in Brecon with CERTAS, your one-stop shop for essentials, local treats, and friendly service.
DIXIES CORNER
16.8 km
Brecon's trusted specialist in authentic military surplus and outdoor gear since establishment.
Beacons Antiques
16.9 km
Discover timeless vintage treasures and unique collectibles at Beacons Antiques, a charming hub of history in the heart of Brecon.
Kitty Keane's Vintage
16.9 km
Discover authentic Welsh vintage and handcrafted treasures at Kitty Keane's Vintage, a charming craft shop in the heart of Brecon.
Tŷ Cariad
16.9 km
Discover authentic Welsh crafts and unique gifts at Tŷ Cariad, Brecon’s cozy hub for local artistry and culture.
Get Connected
16.9 km
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.
For the vibe & atmosphere seeker
- Relaxing
- Tranquil
- Scenic
- Fun-filled
For the design and aesthetic lover
- Rustic Designs
For the architecture buff
- Historic
- Parks & Gardens
For the view chaser and sunset hunter
- Iconic Views
- Panoramas
- Waterfront
- Sunset Spots
For the social media creator & influencer
- Instagrammable
- Photo Spots
- Selfie Spots
For the eco-conscious traveler
- Eco-Friendly
- Protected Area
- Public-Transport Accessible
- Locally Managed
- Wildlife Habitat
For the kind of experience you’re after
- Nature Escape
- Photowalk
- Day Trip
- Cultural Heritage
- Mindfulness
For how adventurous you want the journey to be
- Easy Access
Location Audience
- Family Friendly
- Senior Friendly
- Child Friendly
- Teen Friendly
- Wheelchair Access
- Pet Friendly
- Couple Friendly
- Solo Friendly
