Sandanski

Sandanski sits in the warm, dry Struma valley under the Pirin mountains, close to the Greek border, and it is one of Bulgaria's best-known spa towns. More than 80 mineral springs around it run from about 42 to 81 C, and the town is especially associated with stays for people with breathing complaints because of its mild climate. You soak in hotel complexes rather than in nature.

Interhotel Sandanski, next to the city park, sells day passes to non-guests at about 45 BGN for adults: an outdoor pool at 30 to 32 C, an outdoor thermal pool at about 38 C, a 25 m indoor pool and a spa floor with sauna and steam. Lifeguards are on duty. The drive from Sofia takes 2 to 2.5 hours on the Struma motorway, and buses run from Ovcha Kupel station.

Pair it with the free outdoor pools at Rupite, about 20 km away. The honest downside: some dates are reserved for hotel guests only, and summer weekends are crowded, so check before driving in for the day. Prices were quoted in leva; Bulgaria moved to the euro in 2026.