This is the initial release of the R package Spacer2PAM. The package allows users to predict PAM sequences for a CRISPR-Cas system from CRISPR array spacers and guides experimental determination of functional PAM sequences. This version is documented in a publication titled "Spacer2PAM: A computational framework to guide experimental determination of functional CRISPR-Cas system PAM sequences" published in Nucleic Acids Research with DOI: 10.1093/nar/gkac142