About the Place
Brownsea is part National Trust and partlly owned by the John Lewis company. If you wish to land on the island then it helps to be an NT member as you can be charged otherwise. Ferries run there from Poole Quay.
Brownsea Island Swim
There are a maximum of forty spaces available per year for this round the island swim
https://www.rlss-poole.org.uk/brownsea/
Camping on Brownsea
You can camp there right up until the 30th September
https://www.nationaltrust.org.uk/holidays/campsite-brownsea-island-dorset