Crymlyn Bog National Nature Reserve, near Swansea

Welcome

Crymlyn Bog is the largest lowland fen in Wales and its extensive reed and sedge beds are home to a wide variety of wetland plants, birds and insects.

The best way to experience this National Nature Reserve is to walk the trails which include boardwalks through the heart of the fen.

Crymlyn Bog is one of the most important wetland sites in Europe and its survival is remarkable considering its location next to industrialised Swansea.

Over the years, its neighbours have included an oil refinery, power station and rubbish tip, together with numerous coal mines and other industrial works, and yet the bog has remained largely intact.

Nearby is the slightly smaller National Nature Reserve of Pant y Sais, where there is a short boardwalk accessible for wheelchair users.

Walking trails

The walking trails are waymarked from start to finish.

Look out for the information panel at the start of the trails.

Find out about walking trail grades.

Bog Walk

• Grade: easy
• Distance: 1 mile/1.4 kilometre
• Time: ¾ hour
• Trail information: The trail follows level grassy tracks and sections of boardwalk. There are several gates. Please stick to the boardwalks as there is dangerous wet ground. Horses and ponies graze here – do not approach or try to feed the horses; keep dogs under close control, move round the herd and shut gates behind you.

This walk follows the boardwalks out into the heart of the fen.

Listen out for the calls of reedbed birds in early summer and look out for the display of wildflowers in spring and summer.

Bog and Balloons Walk

• Grade: easy
• Distance: 1¼ miles/2.21 kilometres
• Time: 1 hour
• Trail information: The trail follows level grassy tracks and sections of boardwalk. There are several gates. Please stick to the boardwalks as there is dangerous wet ground. Horses and ponies graze here – do not approach or try to feed the horses; keep dogs under close control, move round the herd and shut gates behind you.

This slightly longer walk also follows the boardwalk but it returns via the ‘Balloon Field’.

This was the site of a World War Two barrage balloon to deter German air attacks on the Llandarcy oil refinery – you can still see the circular concrete anchor points set in the ground.

What to see at the National Nature Reserve

The extensive reed and sedge beds are home to a wide variety of wetland plants, birds and insects.

Reedbeds great for birds

Large numbers of reed warblers and sedge warblers breed here, along with Cetti’s warbler, grasshopper warbler, reed bunting and water rail.

In early summer the reserve is alive with the sound of birdsong as they set up their territories.

Scarcer visitors, normally found in the East Anglian fens, include marsh harrier, bearded tit and the elusive bittern.

You can also see buzzard, kestrel, sparrowhawk and red kite flying over the reserve.

Fantastic fen for bugs

Easiest of all to spot are the numerous dragonflies and damselflies that hover and dart across the bog’s open waters.

Butterflies are plentiful, too, such as the yellow brimstone.

Britain’s largest and rarest spider, the fen raft spider, lives here. It is confined to open water areas and so you are very unlikely to see one during your visit.

Wetland flora

Amongst the reed and sedges, special wetland flowers include yellow iris, marsh cinquefoil and greater spearwort.

Look out for the big clumps of royal fern which is a Crymlyn speciality.

National Nature Reserves in Wales

There are over 70 National Nature Reserves in Wales.

National Nature Reserves are places with some of the very finest examples of wildlife habitats and geological features.

Find out more about National Nature Reserves.

Opening times

The car park barrier is locked overnight.

The visitor centre is only open for pre-booked visits or events.

How to get here

Location

The car park for Crymlyn Bog is accessed by narrow roads from the Fabian Way (A483 dual carriageway). It is one mile (1.6 kilometres) from the A483.

The reserve is in the county of Swansea.

Ordnance Survey map

Crymlyn Bog is on Ordnance Survey (OS) map 165.

The OS grid reference is SS 685 942.

Directions

From Swansea city centre: follow the A483 (Fabian Way) east out of the city centre towards Cardiff. Pass a large retail park and cross over the river. 100 metres after the junction for the Fabian Way Park and Ride, turn left immediately after the BMW service garage and by the Mile End pub. Follow this road (Wern Terrace) and turn right at the T junction with Tir John Road. Follow this narrow lane, bearing left at the entrance to the civic amenity site onto Dinam Road. After ½ mile, the car park is on the right.

From M4: Exit on Junction 42 onto A483 (Fabian Way) to Swansea city centre. Pass Swansea University’s Bay Campus on the left and then turn right at junction for Fabian Way Park and Ride. Turn around in the Park and Ride and rejoin the A483 travelling east back towards the M4. Turn left after 100m (immediately after the BMW service garage and by the Mile End pub). Follow this road (Wern Terrace) and turn right at the T junction with Tir John Road. Follow this narrow lane, bearing left at the entrance to the civic amenity site. After ½ mile, the car park is on the right.

Public transport

There is a bus service to Port Tennant, about half a mile away.

For details of public transport visit the Traveline Cymru website.

Parking

Parking is free of charge.

The car park barrier is locked overnight.

Overnight parking is not permitted.

Closures and diversions

• Sometimes we need to close or divert trails for your safety whilst we undertake maintenance work or other operations.
• We may have to close a site in extreme weather, such as high winds or snow and ice, due to the risk of injury to visitors or staff.
• Please always follow any instructions on site and any temporary diversion signs.

Contact details

There are no staff at this location.

Contact our customer team for general enquiries during office hours, Monday to Friday.