We have studied the feasibility of activated carbyne as a good hydrogen storage material. Density functional theory (DFT) simulations through van der Waals interactions have been applied to investigate calcium sorption on activating carbyne with zinc dichloride (ZnCl 2 ) and also interactions of molecular hydrogen with pristine carbyne and Ca functionalized on an activated carbyne C 12 -ring. The obtained results showed that (i) the chemical activation of the C 12 -ring with ZnCl 2 increases its area by 5.17% with respect to pristine carbyne. (ii) Ca atoms at small concentrations tend to get atomically sparse on carbyne, donating +0.94e and +1.05e to the ring, according to Mulliken population analysis and the electrostatic potential fitting charges, respectively. Furthermore, in the presence of calcium, hydrogen sorption increases by 21.8% in comparison with Ca-decorated pure carbyne. (iii) Seven hydrogen molecules per Ca atom have adsorption energy close to the range of ∼0.3–0.5 eV per H 2 , which is necessary for effective charge/discharge cycles. (iv) Theoretical uptake (7.11 wt %) with a single Ca atom is higher than the U.S. Department of Energy target (5.5 wt %). Therefore, an activated C 12 -ring can bind three Ca atoms with its seven H 2 molecules reaching 13.8 wt %. (v) Equilibrium pressure for CaC 12 –7H 2 and Ca 3 C 12 –21H 2 systems (5–15 MPa) by means of adsorption isotherm calculations. The calculated van’t Hoff desorption temperatures exceed considerably the boiling point of liquid nitrogen. In addition, we also performed DFT-based molecular dynamics simulations for the C 12 , CaC 12 , CaC 12 –7H 2 , and Ca 3 C 12 –21H 2 systems to study thermal stability. Our results confirm the potential of Ca-decorated carbyne for hydrogen storage.