Go for a stroll by the water's edge and get some fresh air at Christchurch Harbour. It's always relaxing watching the boats as they come and go.
You'll be spoiled for sightseeing choice when visiting Christchurch. Christchurch Harbour is a good place to kick off here, but there are lots of other interesting places to check out. Bournemouth Beach, O2 Academy Bournemouth, and Bournemouth Pier are not far from the place for ships to anchor and and will cap off your day nicely.