This paper presents a review of the adoption of elliptic curve cryptography (ECC) algorithms in X.509 digital certificates. It was analyzed the cases of Estonia, United Arab Emirates (UAE), Australia, Brazil, and Egypt. Although all five countries have considered using ECC algorithms, only two (Estonia and UAE) use them throughout their entire PKI hierarchy (root, intermediates, and end-entity certificates). Our findings complement those of Bos et al. [1], which in 2014 identified only Austria as an adopter of ECC in end-entity X.509 digital certificates for electronic signatures.