Thessaloniki has one dedicated gay sauna, AquaSplash — the relocated and rebranded successor to the long-running Splash — in the Vardaris district near the centre. It is a men-only space with the usual sauna, steam and relaxation facilities.
For cruising, the centre also has men-only venues such as Play and Blue Vision near Vardaris. If you are looking for more choice, Athens lists further gay saunas.
What else Thessaloniki offers: a compact cluster of dedicated gay bars and clubs around Valaoritou and Vardaris, gay-friendly dining in Ladadika, and a range of central hotels. Those listings are real, checked, and kept current.