There isn’t much to do in Oia to be honest. All you need is just to walk around, admire the massive accumulation of white houses and the famous blue domed church, climb various stairs, check one of those stores featuring jeweleries, handicrafts or clothes, or simply buy a beer or coffee and sit down in a place with a view.
If you live in Fira, you can easily catch a bus from the central station to Oia. The town isn’t very big, but it’s still quite some distance from Fira and I wouldn’t recommend walking. However, you might also choose to walk from Fira to Imerovigli, along the seaside through stairs and narrow lanes, the pace would be slow but view is stunning. You can choose to climb to the Skaros Rock too. Then from Imerovigli, catch the bus to Oia. Often it would be full so you might not have a seat.
As a bookworm myself I have always loved libraries and bookstores. So I do recommend stopping at the lovely and cute basement called Atlantis Books. Here you can buy some books in various languages, from English to French to German, on various topics and subjects too. An adorable cat sleeps near the entrance, so does the dog. This is very common here in Santorini, probably the warm weather makes those little creatures too lazy. You see them lying in the shade everywhere, don’t even bother to open their eyes when someone passes by.
Of course, one should not miss the sunset in Oia, even though I personally think sunset in Fira is more beautiful. The Byzentine Castle Ruin is the best spot for the sunset viewing, but it can also be very chaotic and extremely crowded, staring from 2 or 3 hours before the sunset time even. People gather here to get the glimpse of the sun sinking into the sea, and many photographers spread their tripod trying to get the best shots. It is also very windy, especially on the edge of the cliff.
However, the view is beautiful, and I especially love to see the evening descending on those white houses with the sparingly warm yellow lights dotted. At this time it would be slightly less crowded also, but persistent photographers stay. At least the major “battle” was over, now I could enjoy a little tranquility of the town in the evening.
ANNA HOLTBLAD white dress EU S | VAGABOND shoes EU 36 | straw hat with 15 cm brim | BRIC A BRAC red dress EU XS (altered myself to fit petite)| vintage bag