Tal-y-llyn is a lake, not the railway. It lies below Cadair Idris, and its Welsh name is Llyn Mwyngil.

The walk round the lake is an easy circuit of 2.5 to 3.8 miles, depending on whose route you follow.

A fit walker can add the climb to Llyn Cau, a mountain lake reached from the Dôl Idris car park.

The lake and its Welsh name

The walking guide website Walking Englishman gives the proper Welsh name of the lake as Llyn Mwyngil.

The regional visitor guide Visit Mid Wales calls it a 220 acre ribbon lake (a long, narrow lake) at the foot of Cadair Idris.

It adds that the River Dysynni flows from the lake through Abergynolwyn to the sea north of Tywyn.

Llyn Mwyngil and Tal-y-llyn are the same lake.

The lake circuit in figures

The guides do not agree on the length of the circuit, because their circuits differ. Each figure below belongs to the route named beside it.

Two walkers on a path above a small old stone church with a slate roof at the end of a lake.

  • Walking Englishman gives 3.8 miles (6.2 km) from Tal-y-llyn, with 209 m of climbing, about 2 hours, graded Easy.
  • The walking route website GPS Routes gives 2.5 miles (4 km) for its Tal-y-llyn Lake waterside walk.
  • The route planner Komoot maps a loop from Dolffanog Fawr at 4.89 km.

Komoot’s mapped loop is mostly road: 4.12 km of the 4.89 km.

The other 782 m is path.

Walking Englishman says the walk gives views from both lakeside and ridge. It lists Ordnance Survey Explorer map OL23.

It also notes that low-flying aircraft may break the natural silence, because Tal-y-llyn lies on the Mach Loop.

For birds, it names common sandpipers, dippers, grey wagtails and little grebes at the west end. Tufted ducks, coots and cormorants are noted in the marshland at the east end.

Road, path and the boggy fields

The local walks site Dolgellau.Wales ends one long walk by going round the lake anticlockwise. It asks walkers to be wary of the traffic on the far side of the lake, the B4405.

Just after the lake ends, a footpath sign marks a cut across the fields. That path rejoins the quiet road.

The same site gives a shorter option: the quiet road, then the B4405 for the final quarter of a mile.

The walking blog Walking Away went clockwise instead. It says one side is a tarmac road, and it calls the two fields at the end of the lake extremely boggy.

Expect traffic on the B4405 and wet ground in the fields.

Starting points around the lake

You can start from any of these:

  • Tal-y-llyn village: Walking Englishman starts at grid reference SH 71044 09417. St Mary’s Church stands in the village on an ancient site, and part of the present building dates back to the 13th century. It has old painted panels above the altar.
  • The hotel car park: the blog Walking Away began at the Ty’n y Cornel Hotel, which the hotel says stands on the shores of the lake. In 2024 the blog said the hotel has a car park.
  • Dôl Idris: Natural Resources Wales (NRW), in its Cadair Idris nature reserve guide, says the Eryri National Park Authority manages the car park. Per Walking Away, it is about a mile along the main road from the lake.

GPS Routes mentions a lakeside hotel at the south western end where you can get a Welsh cream tea.

For Dôl Idris, turn onto the B4405 from the A487 and the entrance is immediately on the right.

The grid reference is SH 732 115. NRW says the postcode, LL36 9AJ, covers a wide area and will not take you to the entrance.

Dôl Idris charges for parking, and the Visit Wales website says it accepts card payments only. That was the position in October 2026.

The Park lists accessible toilets, accessible picnic tables, a visitor centre and a seasonal tea room. It also lists a 1.25 km accessible parkland path, 0.75 hours.

The Park says the T2 bus between Aberystwyth and Bangor stops at “Minffordd, Hotel for Cader Idris”.

The climb to Llyn Cau

GPS Routes suggests the climb to Llyn Cau as the way to extend lakeside walking.

A dark corrie lake below a huge curving wall of cliffs, a walker small on the shore.

GPS Routes gives its Llyn Cau walk from Dôl Idris as 3.7 miles (6 km), going up and coming back the same way.

It gives no time.

It calls this “still quite a challenging walk”, though not as strenuous as the longer climb to the summit.

The Park’s route sheet gives these steps from the car park:

  1. Go through the kissing gate by the toilets at the far end of the car park.
  2. Continue past the visitor centre and over the bridge.
  3. Go through a small gate at the bottom of the steps, then make a steep climb.
  4. Go through another small gate in a dry-stone wall, to the end of the forest and open mountain land.
  5. After about 200 m, at the first fork, bear left with the river on your right. Do not cross the bridge.
  6. Go left round a marshy area, then follow the stone-pitched path uphill to a second fork.

At this second fork, the path to your right leads to Llyn Cau.

At the second fork, the path to the left aims towards the summit.

NRW says the Gorge Climb, which follows part of the Minffordd Path, climbs 140 m one way. It has many flights of stone and timber steps.

The Park grades the full Minffordd Path to the summit Hard/Strenuous. It goes through Cwm Cau, where Llyn Cau lies, and the climb to the summit has its own guide.

NRW describes sheer cliffs, a thousand feet tall at one point, almost encircling Llyn Cau, one of Wales’ deepest natural lakes.

The lake, not the railway

The Talyllyn Railway is a separate thing. Its heritage steam engines run from Tywyn, on the coast, to Nant Gwernol, above Abergynolwyn, says the railway’s own site.

The railway’s line runs for more than seven miles, from Tywyn to Nant Gwernol.

For Dolgoch Falls on the railway’s line, see the waterfalls of Snowdonia.

We compile and explain public route and safety information. We guide nobody and sell nothing on the hill.

Choosing between the lake and Llyn Cau

  • Low cloud, rain or tired legs: walk the lake. Walking Englishman gives 209 m of climbing for its whole circuit.
  • Clear weather and strong legs: climb to Llyn Cau, 3.7 miles out and back by GPS Routes.
  • For a longer walk: Dolgellau.Wales joins Llyn Cau, Mynydd Pencoed and the lake in 9.2 miles, or 7.2 miles without the lake circuit. The full walk has 2,900 feet of ascent.

For a flat walk nearer Dolgellau, try the Mawddach Trail.

If cloud is down on the cliffs, walk the lake instead of climbing to Llyn Cau.

Check the mountain forecast before you leave the car park.