私人兑换外币是不合法的，私自买卖外汇、变相买卖外汇、倒买倒卖外汇或者非法介绍买卖外汇数额较大的，由外汇管理机关给予警告，没收违法所得并处罚款，所以私人兑换外币是违法的。Like my do the job? Don't forget to assistance and clap, let me know that you're with me about the