I have done most of my diving in the central region of Chile. The water there is fairly cold and visibility is not great, but the large number of wrecks makes diving there very exiting. I usually dive with the Andisub dive operation for which I also sporadically worked as an instructor. This dive operator is very professional and has great knowledge of the many wrecks around the bay of Valparaiso. As you can see from their website the primary language for the operation is Spanish, but they usually have someone on staff that knows enough english to successfully coordinate a dive trip. Also note that the address in the web page is outdated as they have recently changed to the following address:

Andisub
7 y 1/2 Oriente 425
Vina del Mar
CHILE
+56(32) 2967856