A. In Episode 4, of Season 6, "A Horse of a Different Color".
Brother Sam, a reformed convict from the Good Shepherd Auto Repair, has invited Dexter to a "baptism / BBQ" at the beach.
Dexter
shows, up with young Harrison in tow, and critically watches as Brother
Sam dunks one of his followers (Nick) in the water. Afterward, Sam talks with
Dexter about belief in things bigger than oneself.
Later, in
Episode 6 ("Just Let Go"), Dexter takes Sam's killer, Nick, to the same
beach where he was baptized, and confronts him with the fact that he
killed a decent man who treated him well.
On his
deathbed, Sam had asked Dexter to tell Nick that he forgave him.
Dexter tries to honor his friend's last wish, but when Nick gleefully brags that he can get
away with murder because there are no witnesses, Dexter loses control and
drowns Nick.
After that drowning, Dexter looks up to see his dead brother, Rudy/Brian.
Q.
What is it actually in real life?
A. A beach - but not in Miami.
Q.
Where can I find it in real life?
A. This is Bayshore Beach,
a small sheltered beach on the east side of 54th Place, just
north of E. Ocean Blvd, where the Long Beach peninsula joins the mainland
- about a mile southeast of the Belmont Pier.
For one reason or another, locals refer to this beach as "Horny Corner".
The beach doesn't face the ocean.
In fact, it faces the opposite direction. The calm water you see is
the Alamitos Bay, which runs between the peninsula and Naples Island,
(which is what you see on the other side of the water).
The beach
park includes a small cluster of sporting facilities, playground equipment
for kids, and a co-op pre-school.
There's also a small snack stand called Alfredo's Kayak Cafe, where Dexter has have filmed a number of scenes over the years, including Dexter's first meeting with Rudy (ironic, considering his "reunion" with Rudy on this same beach), and Lundy dining with Debra.
Look at the
5th screencap down on this page, and you can see the semi-pyramidal handball courts
behind Dexter's head, with a glimpse of the café to the left.
They've shot other scenes at Bayshore Beach as well (not involving the Cafe), including the scene
where Lila bought roofies from a drug dealer was shot
near the basketball courts. And the scene where Dexter planted evidence
against Doakes was shot at the end of the adjacent
pier.
It's right across the street from the beach where they filmed both the Bimini scene, and the scene of Travis freeing the captive. And it's just a short walk northwest of Deb's new beach house.
I shot the photos below in 2008.
In my photo below, the camera is looking north. The homes you see are on Naples Island.
A. Dexter has
filmed at this small beach so many times in the past (beginning back in
the first season), that I'd recognize itd features anywhere: The
homes on Naples Island visible across the channel, the handball courts
visible in the background, the small dock... I've been there and shot
photos on several different occasions.