Rincon is great for that. I would surf Domes or Marias in the morning, head back and get my dive gear and go dive "steps"...otherwise known as Tres Palmas, of course if there is BIG surf, Tres will be breaking at double to triple overhead.
I recommend getting a flight into Aguadilla rather than San Juan if that would be your only destination. Of course there are lot's of great surf spots on the north coast heading toward Rincon.
Enjoy yourselves, I personally liked PR about as much as Costa Rica which I've spent about 6 months in.
PS- My avatar is the break known as Domes, pic taken from the lighthouse. This was a small day, maybe head high.....Also most of the breaks are shallow water Reef breaks. If you aren't very experienced, places like Sandy Beach might be better for you.
