The Bristol Channel (Môr Hafren) is a major inlet in the island of Great Britain, separating South Wales from the West Country and extending from the lower estuary of the River Severn (Afon Hafren) to that part of the North Atlantic Ocean known as the Celtic Sea (Môr Celtaidd). It takes its name from the English city of Bristol and is over 30 miles (50 km) across at its widest point.

The lower limit of the Bristol Channel is St Govans Head in Pembrokeshire, Lundy Island, and Hartland Point in Devon. The upper limit is a straight line between Sand Point, Somerset and Lavernock Point in South Wales. East of this line is the Severn estuary. Western and Northern Pembrokeshire and North Cornwall are outside of the limit of the Bristol Channel, and are considered part of the seaboard of the Atlantic Ocean, although Bude in North Cornwall during the industrial era was often called by sailors on their way to Cardiff as "the gateway/entrance to the Bristol Channel".

The Bristol Channel, on both the South Wales and West Country sides, has more miles of Heritage Coast seaboard than any other stretch of water in the United Kingdom. Heritage coastlines include Exmoor, Bideford Bay, the Hartland Point peninsula, Lundy Island, Glamorgan, Gower Peninsula, South Pembrokeshire and Caldey Island.

In 2004, The Times "Travel" magazine selected Barafundle Bay in Pembrokeshire as one of the best 12 best beaches in the world, and in 2007 Oxwich Bay made the same aforementioned magazine's Top 12 best beaches in the world list and it also selected Oxwich as Britain's best beach for 2007. The Bristol Channel and nearby Celtic Sea beaches of Wales, North Devon and North Cornwall are acknowledged by many travel magazine writers as the best in the U.K for sand/water quality.