Kamay Bay National Park is situated in Kurnell, about 50 minutes south of Sydney.
Barrawang walk, starting at the main car park / visitor’s centre, takes you down to Captain Cook’s landing spot and also an interesting sculpture on the water’s edge. It’s an easy 1.2km loop and a large part of it is wheelchair accessible. There is are also a grassed picnic area with tables.
Kape Solander is a great viewing spot for whales. You can either drive there or get there via a 40 minute (one way) walk from the visitor centre. The walk through the bush isn’t all that interesting, so I’d suggest driving instead. Keep in mind during whale watching season (mid June – mid July and September – mid November) it can get very busy on the weekends. Try to get there early to avoid traffic delays and the possibility the park may be closed to further visitors.
Overall verdict, decent spot for a picnic, whale watching and some history but if you are after a good bushwalk, there are better options.
https://www.nationalparks.nsw.gov.au/visit-a-park/parks/kurnell-area