| Mochras | |
|---|---|
 Mochras above Llandanwg village | |
  Mochras Location within Gwynedd | |
| OS grid reference | SH552265 |
| Principal area | |
| Preserved county | |
| Country | Wales |
| Sovereign state | United Kingdom |
| Post town | LLANBEDR |
| Postcode district | LL45 |
| Dialling code | 01341 |
| Police | North Wales |
| Fire | North Wales |
| Ambulance | Welsh |
Mochras (also known in English as Shell Island) is a peninsula lying west of Llanbedr in Gwynedd, Wales. The peninsula was formed after the River Artro was diverted by the Earl of Winchilsea in 1819 from its previous course where it entered the sea to the south of Mochras. Prior to this, access to the ancient settlement on the 'island' would have been through the village of Llandanwg, which is now across the estuary.
Mochras is known for the wide variety of seashells that wash up on the beach, and for its wild flowers. It is said to have been connected to the mythical Cantre'r Gwaelod.
The peninsula lies within the Snowdonia National Park. From the end of October to the following March local farmers bring their sheep from the lowlands to graze on the 'island'.