This spectacular coast walk is in the Algarve, Southern Portugal, near Armação de Pêra (between Lagos and Albufeira). Unlike most of our walks, it isn't (sadly) in the south east of England. However, if you only do one walk in you lifetime, do this one.
This part of the coast has karst limestone cliffs - think the island in the James Bond film "The Man with the Golden Gun". It often features on the cover of Portuguese guidebooks. The limestone cliffs are easily eroded, so there is a spectacular mix of headlands, arches, stacks, caves, blow holes (a hole in the roof of a sea cave - from the cliffs, you can look down in to it), coves, and sandy beaches for swimming. You can even walk through arches under headlands between some beaches, all of which have cliff access.
The cliffs are quite low, so exploring the area, and going down to each beach in turn for a swim, is quite easy.
It is an out and back walk, so you can walk as short or long a distance as you like before turning back. There are several places along the walk with road access. Take your time, explorer the beaches and headlands, take lots of photos, have a swim, and a drink or 2 on the terrace. The colours would be great at dusk.
The eastern half walk is fairly rural, with only a few access roads and seasonal beach cafes, with no seafront development. The western half of the walk forms the 5.7 km long waymarked "PR1 LGA Percurso dos 7 Vales Suspensos" (7 Hanging Valleys Path) which passes the coastal villages of Benagil (fishing harbour), Carvalho, and Vale Centianes
The walk is possible year round. High summer may be too hot for walking, and be busy, but the sea will be warm, and it averages 14 hours of sunshine a day. Spring and early Autumn would be best. Winter (when the photos were taken) can be nice, still sunny, but the sea is a little colder, but not too bad (17°), for swimming. There is rain from October to February, but very little from May to September
If you've come all this way, there are other good coastal walks around Sagres (the south west corner) and Pontal (the west coast)