Catalysis of the reaction: O-phospho-L-serine + H2O = L-serine + phosphate, on a free amino acid.
Source:PMID:9188776,
RHEA:21208,
PMID:25037224
Comment
Do not confuse with protein phosphatases. For protein phosphatases, consider GO:0004722 ; protein serine/threonine phosphatase activity or GO:0008138 ; protein tyrosine/serine/threonine phosphatase activity.