We prove sharp decay estimates for critical Dirac equations on R n , with n 2. They appear, e.g., in the study of critical Dirac equations on compact spin mani-folds, describing blow-up profiles (the so-called bubbles) in the associated variational problem. We establish regularity and integrability properties of L 2-solutions (where 2 is the Sobolev critical exponent of the embedding of H 1 2 (R n , C N) into Lebesgue spaces) and prove decay estimates, which are shown to be optimal proving the existence of a family of solutions having the prescribed asymptotic behavior.