Yes, there is an Athenian Riviera, and very beautiful it is too. It stretches from the city to Cape Sounion. The coast road is spectacular, taking you past some of the most expensive properties in the world, in Vouliagmenis, Voula and so on.
You go past Vouliagmenis Lake, which is mysterious, as it is salty, but it seems that sea water doesn’t feed into it. There’s a story about some divers who went into the lake and never came out. You can take to the waters if you pay for the privilege.
The bends on the coast road are not exactly hairpins, although they are bordering on them. Not wonderful if you suffer from vertigo. Luckily, you don’t have to take the same road back to Athens if it’s dark, as there’s another road through Lavrio. This was the ancient port used for exporting the silver found in the locality.
You can stop and swim in one of the many coves and bays en route to Sounio and swim in the turquoise-blue sea. If you go in summer it will be warm, of course, but people swim in it all through the year.
I’ve travelled this road many times, as sometimes it’s good to get out of the city and eat fresh fish and seafood virtually on the beach, as you can in Sounio (before you get to the temple you take a right down a hill to Hlios and when you get to the bottom, turn left and visit the taverna on the left, on the beach.)
In fact I can thoroughly recommend a trip along the Athenian Riviera. Athens is not the only place to visit while you are in Greece.