Yes. According to Maine’s Health Care Decisions Act, your out-of-state advance directives are valid in Maine if they comply with the laws of the state where you created them.
However, if you have recently relocated, it may be time to review your advance directives. State laws are subject to change, so it’s a good idea to create advance directives that are tailored to current Maine law. You can create an attorney-approved Maine living will with FindLaw in as little as 30 minutes. You don’t even need to leave the comfort of home to do so.