Brownsea Island by third parties, is owned by the National Trust. Most of the buildings are situated near the small landing stage. The northern portion of the island is a Nature Reserve managed by Dorset Wildlife Trust and an important habitat for birds; this part of the island has limited public access. A small portion to the southeast of the island, along with Brownsea Castle, is leased to the John Lewis Partnership for use as a holiday hotel for staff, and is not open to the public. The island forms part of the Studland civil parish in the Purbeck local government district.
Brownsea Island Scout camp posts Scout and Guide flags at the approach to the altar. In 2007, to coincide with the Scouting centenary, about 40 new kneelers or hassocks were given to the church, decorated with the 21 World Scout Jamboree badges and other Scouting, Guiding and island badges. The church is often used for services during large camps. Brownsea Island is generally open to the public from March to October, via ferry from Poole. The island was reserved for Scouts and Scouters on 1 August 2007 during the Sunrise Camp. The National Trust operates a number of events throughout the summer months including