Yes, a venerable Jewish practice to indicate the intent to be restored ritually clean (to be able to enter the Temple, etc) . But it had nothing to do with any remission of sin (ritual impurity is and was never the same thing as sin, indeed it often resulted from perfectly natural processes like menstruation or involuntary emissions, or from complying with God’s commands like His first one about being fruitful and multiplying— no sin involved and thus no remission of sin needed). And of course Jews don’t require baptism to become People of God because they’re born with that status. The Christian baptism therefore resounds in Jewish religious practice but as a Christian sacrament it serves quite different purpses. (Interestingly, there are a couple of verses in the Dead Sea scrolls indicating that that sectarian Jewish community did see baptism as inclusive of sin recissionary import. This is one of several DSS sect distinctives of special interest, but of course they had their dissimilarities also). At any event, Christian baptism came from rge Church’s Jewish roots but has a substantially different theological significance. If we just look at the visible aspect of the water ritual, yes quite the same. But much different meanings so it is best not to confuse the two.
John the Baptist also offered Baptism ~