The Teign estuary is situated on the south coast of Devon and opens into Babbacombe Bay. The estuary runs west to east for some 6.5km from Newton Abbot to the head, to Teignmouth on the northern shore, and Shaldon, on the southern shore, at the mouth. The estuary has a moderate freshwater input, and strong tidal flows are set up in the lower estuary. These flows have scoured a deep pit (9m below chart datum) at the mouth of the estuary. The dominant substrata are soft sediments, these are coarse in nature at the mouth, with an increasing proportion of mud as one moves up the estuary. Hard substrata occur at the mouth of the estuary as the bedrock shores of the Ness, and as cobbles and boulders in the scour pit and at various upper shore sites in the mid-upper estuary. The railway embankment, training wall and the quays provied artificial hard substrata. The area is very popular with tourists and small boat users. The Teign is one of the few south-western estuaries where water skiing and powerboat racing are permitted. Teignmouth is also an important fishing port, with near, and mid-distance trawlers using it as a base. Within the estuary shell fish and oysters and mussels are cultivated, and salmon, trout and bass are taken seasonally by netting. There are few previous marine biological studies which have sampled from the Teign. Twenty-seven intertidal, two sub-tidal diving and seven sub-tidal dredge sites were surveyed. These were categorised into nineteen intertidal and eight sub-tidal communities which are described. Species lists are tabulated. The bend at the mouth provides an abrupt change from exposed to sheltered conditions at the mouth. The bedrock shore at the Ness is moderately rich, and similar to other bedrock shores in the region. The most diverse communities occured on the scoured boulders on Shaldon Pool, where the combination of degree of scour, and the substrate, is probably unique to the Teign. The hard substrate adjacent to the Shaldon Bridge and the lower shore community on the Salty were also diverse. In the mid and upper estuary typical estuarine communities dominate. The scientific interest and conservation importance of the area has been assessed using standard criteria, and the conservation importance of habitats and communities in the area have been provisionally graded as Local, Regional or National Importance. No habitats or communities of National Importance were identified. The rock pools of the Ness, the lower estuary hard substrata lower shore assemblages, the Lanice beds and pools on the salty and the sublittoral communities in the pit off Den Point were identified as being of particular scientific interest or conservation importance.