Q. What is it supposed to be on the show? A. An empty parking lot, out on the docks. Q. Where is it supposed to be on the show? A. Somewhere at the Miami harbor. Q. When did we see it on the show? A. In Episode 12, the finale of Season 7, "Surprise, Motherf**ker!" LaGuerta has just caught Debra in a lie, surprising her with a video tape of Debra buying a can of gas - which she & Dexter used to torch the church where he killed the Travis Marshall. Stunned and worried, we see her in this scene talking to Dexter about the crisis. They are parked in his car, out on an industrial dock (dotted with giant cranes). She has come to him for help, hoping he can "take care of it" as usual, so she is more than a little upset when it becomes clear that he doesn't really know how to deal with LaGuerta. He tells her he will figure it out. Just then, a thump in the back of the car makes Debra jump. She asks him what was that?  He says: "Estrada". She gives him a disgusted look, but resigned now to his murderous ways, she simply leaves the car without saying anything. Q. What is it actually in real life? A. An industrial dock.

Q. Where can I find it in real life?

A. This scene was shot at the Long Beach harbor, near the end of Pier C Street.

It's just 150 feet east of the floating pier where they shot the Doakes flashback, and perhaps 450 feet southwest of the spot where they filmed both the deserted boathouse scene and Estrada's kill-room.

The property appears to belong to Pacific Tugboat, at 1512 E. Pier C Street, Long Beach, CA.

Here is a Google aerial view of the location.  The red arrow marks the spot.

(The yellow X nearby marks the floating dock where they shot the Doakes flashback.)

Q. How the heck did you figure out where it was?

A.  They have filming all season down at the Long Beach harbor, so it was obvious that this scene was filmed there too. The only challenge was finding the exact spot.

Naturally, I looked first at the areas they had used before, starting with the pier where they shot those kill-room scenes. I was looking for that uniquely shaped, red-roofed structure seen to the right of their Dexter's car in the opening wide shot.

I found it quickly - it appears to be some kind of floating barge with a crane aboard - probably for servicing the tugboats. Another large crane is seen on the property in those aerial photos, as well.  I could also spot the line on the blacktop where it changes from a darker shade of gray to a lighter shade (they were parked on the darker side, just past that dividing line).