Varkiza is where the Riviera opens up. The beach is long and sandy, the marina sits at one end, and the housing climbs away from the coast road. It does not have Glyfada's restaurants or Vouliagmeni's lake. It has space. That is the whole argument for staying.
Guests who want Astir for one day and a quieter beach for the rest of the week use Varkiza as the base and Vouliagmeni as the outing. Lagonisi, just south, is the next step if you need a larger garden. The beach itself, with how busy it gets and what the entry looks like, is in the beaches guide.
Villas here should be judged on the drive down to the sand and on the pool, because the coast road is not a place to walk at dusk. We put those minutes in the description. The address stays private.
The airport is further than from Glyfada. Plan the arrival transfer rather than assuming a quick hop, especially with luggage and children. The Athens Riviera guide has the sequence of driving times along the shore.