The Loughor Estuary is situated on the south coast of Wales, forming the north side of the gower and opening into Camarthen Bay. The industrial town of Llanelli lies on the north side of the lower estuary. The area of the middle and lower estuary, which is very broad, is known as the Burry Inlet, and is aligned east-west with the mouth facing west. The mouth is partly occluded by Whiteford Point and the habitats within the estuary are mostly sheltered from wave action. At Loughor the estuary turns north and becomes very narrow, remaining so for most of the upper estuary. The whole estuary is essentially sedimentary and very shallow with large expanses of sediment flats and fringing saltmarshes, and relatively narrow channels. Tidal range is high, at around 8.2 m, and this creates a very energetic environment in the channels. The sand flats below mid tide level are subject to considerable tidal movement and these sands are usually very mobile. Above mid tide level the sands become more stable, and the upper shore areas are often very muddy. The sediments in the upper estuary above Loughor are also mostly muddy. Hard substrata are rare, but there are areas of boulder and mussel scars in the inlet, and the scar at Whiteford Point is quite extensive. The north side of the inlet is considerably affected by man, with harbour walls, sea defences and slag from the industrial furnaces providing some hard substrata on the middle and upper shores. Freshwater flow is quite high and salinities fluctuate greatly between high and low water, throughout the estuary. Boating and other water sports in the estuary are limited by the shallowness of the channels, and the ports of Burry Port and Llanelli are used by relatively small numbers of boats. Large volumes of industrial waste water and sewage are discharged from the Llanelli area with high heavy metal loads, particularly Chromium. The Burry Inlet is famous for its cockle fishery, which is the third largest in the British Isles. Annual landings for 1987 totalled 65, 163 cwt. The fishery is strictly controlled by the South Wales Sea Fisheries Committee, but there has recently been some conflict with bait-diggers who dig the same area. the area of Whiteford scar has been identified as a potentially important mussel fishery, and negotiations between the sea fisheries committee and NCC are in progress. The whole of the Burry Inlet is covered by Site of Special Scientific Interest designations, and Whiteford Point dunes and saltmarsh is managed as a National Nature Reserve. The main conservation interest is ornithological, and the inlet is internationally important for its large populations of waders and wildfowl. The inlet has been proposed as a Ramsar site and a special protection area for birds. Twenty three intertidal and three subtidal dredge sites were sampled during this survey, with fifteen habitats and associated communities described from them. Descriptions of these are given, and lists of species found are tabulated. The habitats and communities are similar to those found in other sedimentary estuaries, with few species of particularly interest. The areas of rich bivalve dominated sediment communities in the Burry Inlet are very extensive, and as such are of great interest. The communities of algae and animals on the mussel scars at Whiteford Point, particularly those on the Lower Shore, are very rich and diverse. Hard substrata elsewhere in the estuary are colonised by typical estuarine communities, and are generally of low diversity. Above Loughor the muddy sediments are colonised by typical upper estuarine communities with low diversity and no species of particular interest. The scientific interest and conservation importance of the area has been assessed using scientific criteria, and the conservation importance of habitats and communities in the area have been provisionally graded as of local, regional or national importance. The mussel scar at Whiteford Point is considered to be of Regional or possibly National importance as are the large areas of rich bivalve dominated sediments in the inlet. The communities colonising the boulders and cobbles at Carreg-fach and the training wall off Machynys Point are also considerd to be of regional interest. Only one species of conservation / scientific interest was recorded, which was the rarely recorded polychaete Ophelia bicornis, found in well drained fine sand at the west of Llanrhidian Sands. It is considered to be of regional importance.