A. A cheap motel - and the show's first crime scene.

Q. Where is it supposed to be on the show?

A. In Miami, Florida.

Q. When did we see it on the show?

A. In Episode 1 (of Season 1), "Dexter".

It's where Dexter first witnesses the handiwork of the "Ice Truck Killer".

Dexter gets a call from his sister, Debra, a policewoman who is working Vice out at what she calls a "sh**hole motel".

There has been a murder there, but her superiors won't let her near the crime scene.  Debra wants to move from Vice to Homicide, and hopes Dexter can help her.

He finds her in room 105 (dressed like a hooker), where she tells him that they found "another hooker chopped up into bits & pieces". She tells him it's the third one, that they're looking for a serial killer.

That, of course, peaks Dexter's interest. But not as much as what he finds in the swimming pool.

Dexter goes down to the motel's (empty) pool and finds a completely bloodless corpse, neatly cut into pieces. (It's the first of many who will be left around Miami.)

Q. What is it actually in real life?

A. An actual motel.

Q. Where can I find it in real life?

A. The motel is actually in Miami.

 (They did a lot of Miami location shooting for the first six or so episodes, then moved filming almost exclusively to L.A..)

They didn't change the name. It's really is called the Seven Seas Motel, and you'll find it at 5940 Biscayne Blvd.

That's between NE 59th Street & NE 60th Street, four blocks in from (east of) Dexterean, in Miami's Bayshore district.

In the opening shots, the camera is looking west/southwest (across Biscayne Blvd) towards the motel. The pool is right out front.

(That's about six miles southeast of Dexter's apartment.)

Here is an aerial photo of the location. And here is a map link.

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

A. Tracking down Miami locations (when I live in L.A.) isn't easy, but this one was easy.

"Seven Seas" was the actual name of the motel.  I just looked it up in the Miami Yellow Pages, then used Live Local's aerial photos to confirm it.