Calcareous sand has been used as the main filling material in numerous reef constructions. Therefore, understanding its long-term dynamic engineering geological characteristics under cyclic applications of traffic or wave loading is crucial to the design and prediction of the serviceability of reef infrastructures. Considering this, seven monotonic triaxial tests and 33 high-cycle (25,000 cycles) drained triaxial tests were conducted on calcareous sand with various mean effective stresses (p’) and cyclic stress ratios (ζ). The results show that the development of the accumulated axial strain (ε₁^acc) has a strong correlation with the positional relationship between the cyclic stress path and critical strength line (CSL) or static strength envelope (SSE) in the p’-q plane. The critical cyclic stress ratio ζ_c, that represents the cyclic stress path reaching the CSL, is proposed. When ζ>ζ_c, the growth rate of ε₁^acc with ζ increases drastically. Moreover, when the cyclic stress path approaches the SSE, ε₁^acc enters an incremental collapse state. The increase in p’ diminishes the dilatancy of the volumetric strain ε_v. However, this response of ε_v reverses from decreasing to increasing with increasing ζ. The resilient modulus (M_r) increases with the number of cycles (N) due to the initial densification. If ε_v dilation occurs, M_r will decrease with N as particles lose contact. A single parameter for the cyclic stress path ratio (ψ) considering the effects of p’, ζ, and SSE is proposed. Additionally, empirical formulas for calculating the ultimate ε₁^acc and M_r are established. Furthermore, particle degradation significantly worsens ε₁^acc and ε_v, but has a more profound effect on the compressibility of ε_v. This degradation is also detrimental to M_r. A certain deviation trend of the predicted values from the measured values is found to correspond with the relative particle breakage.