Chichester Harbour is a designated Area of Outstanding Natural Beauty offering fabulous walks, birdwatching, sailing/boating, fishing and opportunities for many other leisure activities https://landscapesforlife.org.uk/about-aonbs/aonbs/chichester-harbour
North of Chichester lies the South Downs National Park with a further plethora of walking and other leisure options https://www.southdowns.gov.uk/
Portsmouth to the West is home to The Mary Rose, HMS Victory and other visitor attractions at the Historic Dockyard providing interest and enjoyment for all the family https://www.historicdockyard.co.uk/