Port Erin is a seaside village in the south-west of the Isle of Man, in the historic parish of Rushen. It was previously a seaside resort before the decline of the tourist trade. Administratively it is designated as a village district, with its own board of commissioners. The district covers around 1 square mile, and is adjacent to: Port St Mary to the south-east; the main part of Arbory and Rushen parish district to the north and east; the sea to the west; and an exclave of Arbory and Rushen parish district (including the village of Cregneash) to the south. Following recent residential expansion, the settlement is now contiguous with that of Port St Mary, and on 18 July 2018 Tynwald authorised a public enquiry into the proposed expansion of the district boundary to include some of this expansion.

The name means either iron port or Lord's port. The "Lord" may possibly refer to the parish of the Holy Trinity (Kirk Christ Rushen). Another possibility is that the name is derived from sheear, "westerly". The outer breakwater, visible at low tide only, was an abandoned project constructed in 1863 using the Port Erin Breakwater Railway and saw the first steam locomotive used on the island; a severe storm of 1884 later destroyed the breakwater and it was never rebuilt. Today, a marker buoy shows the extent of the breakwater, and the landward end is still clearly discernible. To the north-east, by the A7 road, are the earthwork remains of a motte-and-bailey castle known as Cronk Howe Mooar, possibly the site of a timber fortification built by Magnus Barelegs c. 1100.

The oldest building in the village is known as "white cottage" or "Christian's cottage"; it was built by William Christian and his family in 1781. The Christian family still own the cottage today.

During World War II the village was the location of Port Erin Women's Detention Camp.