Metallic nanowires show pseudo-elasticity with much higher recoverable strain (usually ∼40–50%) than bulk shape memory alloys (∼8–10%). An ultra-high recoverable strain (∼71%) is revealed in hexagonal close-packed cobalt nanowires by our molecular dynamics simulations, realized via lattice reorientation between 〈1¯1¯20〉 and 〈1¯100〉. The pseudo-elasticity is found to be relevant to the cross-section size and length of the nanowires, which dominates the competition between structural transformation and stacking fault formation which leads to different degrees of pseudo-elasticity.