Poole Harbour and its environment have long been recognised both nationally and internationally as being of high biological importance and is one of the largest examples of an estuary with an enclosed lagoonal character in Britain.

The harbour is mostly shallow and contains a high proportion of intertidal saltmarshes and mudflats. These give way to freshwater marshes, reed beds and wet grasslands on low, poorly drained land above the tidal level, and also transitions to heathland on higher sandy ground and heathland mires in small tributary valleys.

The wetland habitats fringing the harbour support large numbers of wintering, migrating and breeding birds along with many rare and uncommon plants and invertebrates. The harbour bed is important for marine invertebrates such as sponges, tube worms, sea squirts and sea mats, including some that are rare around Britain's shoreline.

Areas of heathland support further rare and uncommon birds, invertebrates and reptiles, while pine woodland on some of the harbour's islands are of national importance for some of England's last surviving populations of red squirrel.

This range of estuarine, wetland and heathland habitats, their large extent and the rare plants and animals they support, together with the large variety and number of birds, means Poole Harbour is recognised as being of national and international importance and the area holds a number of statutory designations which serve to protect the natural environment.

Poole Harbour is designated a Site of Special Scientific Interest (SSSI) a Special Protected Area (SPA) and a Ramsar site. The heathlands surrounding the harbour have been designated a Special Area of Conservation (SAC). Some areas of the harbour have also been declared local and national nature reserves. The harbour is also within an area recognised for its landscape value and part of the Purbeck Heritage Coast and part of an Area of Outstanding Natural Beauty (AONB). The AONB includes all the islands of the Harbour as well as much of the water area.

The south side of the harbour is a quiet area with an advisory 6 knot speed limit.You will also see that the small bays and inlets are areas where birds feed, roost and breed and are particularly sensitive.

Please treat the harbours wildlife with care and consideration!

Environmental code of conduct
Please observe the following code of Conduct while visiting Poole Harbour.

While in the harbour:

• do not land in unauthorised places. The foreshores of the southern side of the harbour and on the islands in the harbour are private property and the permission of the owner MUST be obtained before landing
• be aware of the nature reserves. Birds need to feed, roost and in some cases nest on the foreshores and saltmarshes. Children and dogs must be under control in these areas
• keep away from roosting and feeding birds. Try not to disturb birds swimming or feeding in the water
• do not dump rubbish, oily waste or any other noxious substance in the water or on the foreshore. This is very harmful to the environment and is an offence against the harbour byelaws
• keep noise levels as low as possible. Unnecessary loud and persistent noise disturbs everyone.