come on in

come on in

A polite request or command to enter some place. Come on in, we've got a place at the table ready for you! Thank you for calling over, won't you please come on in?
See also: come, on

come on in

Please enter, as in Come on in, the door's open. This phrase is simply a friendly request to enter one's house or some other place. The related come on in, the water's fine originated as an encouragement (or, sometimes, a command) to a reluctant or fearful swimmer but has been extended to other activities, as in Come on in, the water's fine-this is a great office to work in!
See also: come, on