Valdivia Chile is ideally located on the Valdivia river and in close proximity to the ocean. 
There are several islands which can be explored by taking a riverboat cruise. 
Valdivia also has a number of nice small beaches for you to stroll on and enjoy the ocean.
The Valdivia area is great for fly fishing (remember winter holidays in the northern hemisphere means summer holidays here!)
You can visit 3 historic Spanish forts located in strategic places near the mouth of the river, one of the forts is only accessable by boat, the other two by car or riverboat. 
Possible accommodation includes country cabins and farm holidays providing a great starting point for horse riding and long country walks in the peace and quiet offered by this woody area or for those that would like to stay closer to town the Hostal "Entre Rios" is a great place to stay.
This really is a good place to spend a few days while in Chile.