Poole Harbour in accessed via Poole Bay and the English Channel, which sit to the east of the harbour. As you enter the harbour you will immediately see beaches on either side, Studland beach on the south west and Sandbanks beach to the north east, and several islands dotting the area.
The largest island, Brownsea Islands, is directing in front of the harbour entrance. This is not only the largest of the islands it is also the site where the Roman logboat was located in 1964. Furzey Island lies south of Brownsea Island and Green Island is directly south of Furzey Island. Long Island & Round Island are near Arne Peninsula. Gigger’s Island lies to the west, in Brands Bay and while Pergins Islands is to the north in Holes Bay, a natural tidal lake to the north of the main harbour. Finally, Stone Island, so named due to its ridge of submerged gravel and sand, lies between Drownsea and Studland.
The harbour itself is believed to have been formed at the end of the last Ice Age, when large glacier to the north melted and flooded the area. Eventually erosion and continued flow caused other areas, such as Isle of Wright and Isle of Purbeck to be cutoff, leaving Poole Harbour as the lone estuary of the Frome. Today it is feed by the Frome, as well as several other area waterways.