The 1987 Philippine Constitution recognizes citizenship by blood (jus sanguinis) and permits dual citizenship. Republic Act No. 9225, enacted on 29 June 2003 and known as the Citizenship Retention and Re-acquisition Act of 2003, operationalizes this policy. The law allows former natural-born Filipinos who lost Philippine citizenship through foreign naturalization to reacquire it by taking an Oath of Allegiance without renouncing their foreign citizenship. Crucially, Section 4 of RA 9225 extends derivative citizenship to the unmarried child, whether minor or of age, of any person who has reacquired Philippine citizenship under the Act.

This derivative route is the exclusive legal mechanism for an adult unmarried child to acquire Philippine citizenship (and thereby dual citizenship) when the child did not possess it at birth because the Filipino parent had already naturalized abroad prior to the child’s birth. The provision applies regardless of the child’s current age, provided the child remains unmarried at the time of application. Once acquired, Philippine citizenship is retained for life, subject only to the grounds for loss enumerated in Commonwealth Act No. 63, as amended.

Legal Framework

1987 Constitution, Article IV – Defines natural-born and naturalized citizens and implicitly allows dual allegiance for those who reacquire under subsequent legislation.
Republic Act No. 9225 – Core statute governing retention and reacquisition.
Implementing Rules and Regulations (IRR) of RA 9225 (jointly issued by the Department of Justice, Department of Foreign Affairs, and Bureau of Immigration) – Detail documentary requirements, procedure, and issuance of the Identification Certificate.
Related statutes – Philippine Statistics Authority (PSA) issuances for civil registry documents; Department of Foreign Affairs (DFA) passport regulations; Commission on Elections (COMELEC) rules on absentee voting.

Eligibility Requirements

An applicant qualifies for derivative dual citizenship if all of the following are met:

The applicant is the biological child (legitimate or illegitimate, as long as filiation is established) of a parent who has already reacquired Philippine citizenship under RA 9225 and holds a valid Identification Certificate.
The applicant is unmarried at the exact moment the Oath of Allegiance is taken.
The parent lost Philippine citizenship solely by reason of naturalization in a foreign country.
The applicant is at least 18 years old (adult) on the date of application; no upper age limit exists.

Married adult children cannot use the derivative route and must explore other avenues (e.g., naturalization under Commonwealth Act No. 473), which do not automatically confer dual citizenship.

Prerequisite: Parent’s Reacquisition

The parent must first complete the reacquisition process and obtain an Identification Certificate (IC) from the Bureau of Immigration (BI) or a Philippine Foreign Service Post. The parent’s IC serves as the foundational document for the child’s derivative application. Without it, the child’s petition cannot proceed.

Documentary Requirements

All documents must be original or certified true copies. Foreign documents issued outside the Philippines require authentication by the Philippine Embassy/Consulate or apostille where applicable.

Duly accomplished BI Application Form for Derivative Citizenship (available at BI offices or Philippine Foreign Service Posts).
Original Identification Certificate of the parent who reacquired Philippine citizenship.
PSA-issued birth certificate of the applicant (or foreign birth certificate duly authenticated).
PSA-issued Certificate of No Marriage (CENOMAR) of the applicant, or an equivalent affidavit of unmarried status executed before a consular officer if filed abroad.
Valid foreign passport and one photocopy of the data page.
Parent’s marriage certificate (if applicable) or other proof of filiation.
Two (2) recent 2×2-inch passport-sized photographs with white background.
Any additional documents the BI or consular officer may require to establish the parent-child relationship or to resolve discrepancies.

Step-by-Step Application Procedure

Verification of Parent’s Status
Confirm that the parent’s Identification Certificate is valid and unrevoked. The parent’s IC must be presented in original form.
Document Preparation and Authentication
Secure and authenticate all required civil registry documents. CENOMAR must be dated within six months of filing for in-country applications.
Filing of Application
- In the Philippines: Submit personally at the Bureau of Immigration, Citizenship and Legal Affairs Division, Intramuros, Manila, or at any BI extension office authorized to accept RA 9225 derivative petitions.
- Abroad: Submit at the nearest Philippine Embassy or Consulate General. The consular officer forwards the petition to the BI for final approval.
Payment of Fees
Pay the prescribed filing, legal research, and processing fees in accordance with the current BI Schedule of Fees. Fees are non-refundable.
Oath of Allegiance
The adult applicant must personally appear and take the Oath of Allegiance. The oath is administered by the BI Commissioner (or designated officer) in the Philippines or by the consular officer abroad. The act of taking the oath perfects the acquisition of Philippine citizenship.
Issuance of Identification Certificate
Upon approval, the BI issues an Identification Certificate in the name of the applicant. This IC is the official proof of Philippine citizenship and is valid indefinitely.

Post-Approval Requirements and Rights

Philippine Passport
Present the IC to the DFA to apply for a Philippine passport. Dual citizens may hold both the Philippine and foreign passports simultaneously.
Voter Registration
Register with the COMELEC for national and local elections. Overseas dual citizens may vote under the Absentee Voting Law.
Tax and Military Obligations
Dual citizens are subject to Philippine income tax on Philippine-sourced income and, for male citizens, to the National Service Law (Republic Act No. 7077) when residing in the Philippines.
Property and Professional Rights
Full rights of Filipino citizens attach immediately upon issuance of the IC, including the capacity to acquire private lands, practice regulated professions (subject to reciprocity laws), and engage in businesses reserved for Filipinos.
Effect on Existing Foreign Citizenship
No renunciation is required; the foreign citizenship is retained in full.

Important Legal Notes

The derivative right is personal and non-transferable to spouses or future children. Grandchildren must qualify independently through their own parent’s reacquisition.
Citizenship acquired under this process is irrevocable except for the statutory causes of loss (e.g., express renunciation, naturalization in another country after reacquisition).
Any material misrepresentation in the application constitutes ground for denial or subsequent cancellation of the Identification Certificate.
The unmarried status must exist at the moment the Oath is taken; subsequent marriage does not divest the acquired citizenship.
Processing timelines vary by office workload and document completeness but are generally completed within one to three months from the date of oath-taking.

This procedure, grounded exclusively in RA 9225 and its IRR, constitutes the complete and exclusive legal pathway for an adult unmarried child to secure Philippine dual citizenship through derivative acquisition. All steps must be followed precisely to ensure the validity of the resulting citizenship.