Abstract: This study examines the long-run co-evolution of accommodation supply and tourist demand in two major Romanian spa destinations – Băile Felix-Băile 1 Mai (Bihor County) and Băile Herculane (Caraș-Severin County) – over 2001-2024. Using annual official statistics from the Romanian National Institute of Statistics – Tempo Online (Institutul Național de Statistică, 2025), we compare primary series for accommodation structures, existing accommodation capacity (bed places), accommodation capacity in function (place-days), tourist arrivals, and overnight stays. We further derive three integrative indicators: average capacity per establishment (as a proxy for supply fragmentation), average length of stay (overnight stays/arrivals), and accommodation capacity utilisation (overnight stays/capacity in function). To contextualise destination roles within their regions, we also compute resort shares within county totals for key supply and demand measures. Results indicate a common structural shift toward a more fragmented accommodation base and a strong compression of average length of stay toward short-stay tourism by the end of the period. Both destinations exhibit synchronised demand disruption in 2020 followed by recovery, but with different post-shock profiles and utilisation trajectories: Băile Herculane starts as a high-utilisation system in the early 2000s, while Băile Felix-Băile 1 Mai sustains comparatively stronger utilisation through most of the 2010s, with convergence in recent years. The findings highlight that, under a short-stay regime, utilisation outcomes depend critically on calibrating operational capacity to demand absorption and on strategies that translate arrivals into overnight volume.