Ynyslas is a small village in the county of Ceredigion, Wales. The village lies north of Aberystwyth and to the south west of Aberdovey (Aberdyfi). Resting on the shoreline of Cardigan Bay, the long sandy Borth Sands beach is a mere 0.3 miles from Ynyslas.

The Dyfi Estuary and the River Dyfi are nearby and form part of the border between the counties of Gwynedd and Ceredigion. The sand dunes of Ynyslas are situated between the sea and the estuary beach and are home to the Ynyslas National Nature Reserve. The reserve is dominated by an ever-changing sand dune landscape, which is home to an array of rare plants and wildlife.

Ynyslas at very low tides is an amazing sight as a submerged forest is revealed. Tree stumps of oak, pine, birch, willow and hazel can be found embedded in peat at one metre below the normal surface between high and low water marks. This submerged woodland proves that the coastline used to be further west and that the sea level has risen. Running alongside the village is the Afon Leri which joins the Dyfi Estuary at Ynyslas. With views inland and across the estuary to Aberdovey, Ynyslas is a popular region for walking and contains many trails through the dunes.