No effect really on 1040. Will of course need to file PR return but that must be paper filed and there are restrictions for who can file in PR (I believe only those licensed to file in PR). None of Intuit's products support e-filing to PR, so you might have to look for an CPA or tax preparer who is licensed in PR to file your returns. Has your client considered becoming a bona-fide resident of PR. Tremendous tax breaks if you do, I would consider looking into it (first and foremost, all PR source income is exempt from US tax and certain income is exempt for PR tax as well)