According to the IRS, U.S. citizens and resident aliens who are “bona fide residents” of Puerto Rico during the whole tax year (typically January 1 to December 31) only need to file a federal income tax return if they earn income from outside of Puerto Rico.

Residents of Puerto Rico who are employed by the U.S. government or are members of the Armed Forces must report all income that was received (from the government) on their U.S. income tax return.

Individuals, estates, trusts, and corporations may receive a 3-month automatic extension of time to file by submitting Form AS 2644 (also called “Modelo SC 2644).

For more information, please visit the Departamento de Hacienda de Puerto Rico (official website): www.hacienda.gobierno.pr

Also see the following publications:

IRS Publication 54 – Tax Guide for U.S Citizens and Resident Aliens Abroad 

IRS Publication 570 - Tax Guide for Individuals with Income from U.S. Possessions

IRS Publication 1321 -  Special Instructions for Bona Fide Residents of Puerto Rico Who Mus File a U.S. Individual Income Tax Return

Modelo SC 2644 [Form AS 2644] (Request for Extension of Time to File the Income Tax Return)

IRS Tax Form 4868 (Application for Automatic Extension of Time to File U.S. Individual Income Tax Return)

IRS Tax Form 2555 (Foreign Earned Income)
IRS Tax Form 2555-EZ (Foreign Earned Income Exclusion)