In reply to TCP:
It's a beautiful area and I've done tons of walking and scrambling in the area but no climbing. The rock is often very lose and yes it's alpine only in Pirin.
The main attraction is the 400 meter wall of the North Face of Vihren which I hear has some amazing winter routes, however it is also a very dangerous place, also the whole area being some of the most avalanche prone in winter.
Topo here:
https://www.climbingguidebg.com/cdb.php?f=massiveinfo&idMassive=111
In general, having scrambled in the area, it did not appeal to me for any actual climbing, as the rock seemed chossy. Place is super beautiful though, there is a ton of rock so maybe I'm wrong!
There is a tiny crag with some very limited single pitch nearby Bansko:
Topo here:
https://www.climbingguidebg.com/cdb.php?f=massiveinfo&idMassive=488
If you are interested in alpine climbing, I also recommend the whole area of Rila, which has spectacular alpine, multipitch and even some single pitch sport next to the hut.
The "Kuklata" (meaning the doll) has some super classic multipitch routes between 6a+ and 7c+. You should check them out!
https://www.climbingguidebg.com/cdb.php?f=massiveinfo&idMassive=48
The topos are all in Bulgarian, but give you a general idea. What time of the year are you thinking of going?