The dynamic behavior of TiNi shape memory alloy (SMA) bellows is examined in light of its potential use as elements in seismic protection devices. Dynamic property results obtained from cyclic tests under tension-compression loading of TiNi SMA single-stage bellows, with different shapes and with different heat treatments, are reported as a function of displacement amplitude and frequency. It was found that the displacement–force loops were almost symmetric with respect to the central point for almost all specimens. The normalized secant stiffness diminishes significantly with increasing bulge height as well as displacement amplitude. From hysteretic cycles, an equivalent damping of about 15% was recognized for longtime-aged bellows with relatively high bulge height. Frequencies, in the range of interest for seismic applications, had a small influence on damping values. Under the conditions studied in this research, the bellows had better damping performance in a martensite phase than in a rhombohedral phase. SMA bellows in martensite phase subjected to the longtime-ageing have great potential as an element in seismic devices.