Below is a comprehensive overview of the legal framework and principles governing marriages involving underage parties in the Philippines, with a focus on the distinction between void and voidable marriages, the procedures for seeking a judicial declaration of nullity or annulment, and the legal consequences that follow. This discussion is based on the Family Code of the Philippines (Executive Order No. 209, as amended), relevant Supreme Court rulings, and other pertinent laws.

1. Key Legal Concepts

1.1 Void vs. Voidable (Annullable) Marriages

Under Philippine law, there is a critical difference between a void marriage and a voidable (annullable) marriage:

Void Marriage
A marriage that is void from the beginning (ab initio) is considered never to have legally existed. Even so, Philippine law requires a judicial declaration of nullity for clarity and for purposes such as remarriage and legitimate status of children.
Voidable (Annullable) Marriage
A marriage that is valid until annulled. Certain defects exist at the time of the marriage, but these defects must be proven in court, and a judgment must be obtained declaring it annulled. Until the judicial declaration is made, the marriage is considered valid and subsisting.

When discussing “annulment for void marriage due to underage consent,” it is crucial to note that marriages involving a party who is below 18 years of age are void ab initio and not merely annullable. Meanwhile, marriages where a party is between 18 and 21 years old but lacked parental consent are voidable, not void.

2. Legal Age for Marriage in the Philippines

2.1 General Rule

Under Article 5 of the Family Code, the legal marrying age in the Philippines is 18 years old.
However, for those who are 18 years old but below 21, parental consent is required (Article 14).
For those who are 21 years old but below 25, parental advice (rather than consent) is required (Article 15); the absence of parental advice does not make the marriage void or voidable, but may affect the issuance of the marriage license and could have other legal implications.

2.2 Child Marriage Prohibition

Pursuant to Republic Act No. 11596 (passed in 2021), child marriage (involving a person below 18 years old) is prohibited and criminalized in the Philippines. This further reinforces that marriages involving minors (below 18) are impermissible and considered void under the Family Code.

3. When Is a Marriage Void Due to Underage Consent?

3.1 Marriage Contracted by a Party Below 18 Years of Age

Article 35(1) of the Family Code states:

“The following marriages shall be void from the beginning:
(1) Those contracted by any party below eighteen years of age even with the consent of parents or guardians…”

This provision clearly indicates that any marriage where one or both parties are below 18 is void ab initio, regardless of parental or guardian consent. The nullity is automatic under the law, but a judicial declaration of nullity is still necessary to have a final binding court decree confirming that no valid marriage ever existed.

4. When Is a Marriage Voidable (Annullable) Due to Underage Consent?

4.1 Marriage Contracted by a Party 18 or Older But Below 21 Without Parental Consent

Article 45(1) of the Family Code provides the grounds for annulment (voidable marriages). One such ground is:

“A marriage contracted by any party who, at the time of the celebration, was eighteen years of age or over but below twenty-one, without the consent of the parents, guardian or person having substitute parental authority over the party…”

In this scenario:

The marriage is not automatically void.
It is valid until an action for annulment is filed and granted by the court.

4.1.1 Who May File and Time Limits

Who may file:
1. The parent or guardian lacking consent can file the action.
2. The party whose consent was lacking (i.e., the underage spouse, 18-20 at the time of marriage) can also file.
Time to file:
- If filed by the parent or guardian, they must do so before the underage party reaches 21.
- If filed by the underage spouse him/herself, they must do so within 5 years after reaching the age of 21.
- Once the spouse reaches 26 (21 + 5 years), the ground for annulment based on lack of parental consent can no longer be invoked.

5. Procedure to Declare the Marriage Void or Voidable

5.1 Judicial Declaration of Nullity (for Void Marriages)

Even though a marriage is void from the start if a party was below 18, Philippine law requires a judicial declaration of nullity. This is important to:

Have an official record that the marriage was never valid.
Address issues such as the legitimacy status of children, distribution of property, and remarriage.

Steps typically involved:

Filing a petition in the appropriate Regional Trial Court (Family Court).
Service of summons and compliance with procedural requirements (court fees, documentary filings, etc.).
Pre-trial conference.
Trial (presentation of evidence proving that one spouse was indeed below 18 at the time of marriage).
Court renders a Decision declaring the marriage void ab initio.
Finality and registration of the decision in the civil registry and Philippine Statistics Authority (PSA).

5.2 Annulment (for Voidable Marriages)

When a marriage is voidable (for instance, a spouse was between 18 and 21 without parental consent), an action for annulment may be filed. Until the court declares the marriage annulled:

Filing the petition for annulment with the Regional Trial Court (Family Court).
Jurisdiction: The Family Court of the province or city where the petitioner or respondent has resided for at least six months prior to filing or, in case of a non-resident respondent, where the petitioner resides.
Pre-trial and trial: Evidence must show the existence of the ground (lack of parental consent, proven through birth certificates, affidavit of parents, or other documentary proof).
Court Decision: If the ground is sufficiently proven, the marriage is declared annulled.
Finality and registration of the decree of annulment in the civil registry and PSA.

6. Effects of a Declaration of Nullity or Annulment

6.1 Children

Legitimacy:
- If the marriage is declared void under the Family Code, the children conceived or born before the judgment of nullity are generally considered illegitimate, unless certain exceptions apply (e.g., the concept of putative marriage, where at least one spouse was in good faith).
- In voidable marriages (annulment), children conceived before the final judgment of annulment are still considered legitimate (Article 54 of the Family Code).
Custody and Support:
- Courts will decide custody in the best interest of the child.
- Both parents remain obliged to support their children.

6.2 Property Relations

In a void marriage:
- If both parties acted in bad faith knowing that one spouse was underage, property acquired during the “marriage” is typically owned by each partner according to their respective contributions (co-ownership rules).
- If one party acted in good faith (a putative spouse), then the property regime can be treated as if it were a valid marriage for that innocent spouse, but only up to the share corresponding to the spouse in good faith.
In a voidable marriage:
- If the marriage is annulled, the property regime (e.g., absolute community or conjugal partnership, whichever applied) is dissolved, and assets and debts are liquidated in accordance with the law and any relevant prenuptial agreements.

6.3 Right to Remarry

A person who obtains a final and executory decree of nullity or annulment is legally allowed to remarry.
A subsequent marriage contracted without the final decree is considered bigamous and void.

7. Recent Legal Developments and Considerations

7.1 Republic Act No. 11596 (Anti-Child Marriage Law)

Enacted in 2021, this law criminalizes the act of marrying or cohabiting with a minor, as well as arranging or officiating child marriages.
This statute further cements the principle that marriages involving individuals below 18 are not only void but also punishable by law.

7.2 Public Policy Against Child Marriage

Even before R.A. 11596, the Family Code had rendered any marriage involving a minor (below 18) void ab initio.
The new legislation heightens awareness, protects minors from forced or arranged marriages, and imposes punitive measures on perpetrators.

8. Practical Points and Advice

Consult a Lawyer:
- Given the complexities of court procedures, especially proving nullity or voidability, it is crucial to seek professional legal counsel.
Gather Documentary Evidence:
- Birth certificates, marriage certificates, affidavits from parents/guardians can be essential in establishing grounds.
Consider the Welfare of Children:
- Issues of custody, support, and legitimacy need careful handling.
- Courts primarily focus on the best interests of the child.
Register the Court Decree:
- To effect the nullity or annulment, the court decree must be recorded with the Local Civil Registry and the Philippine Statistics Authority. This ensures that the civil status is updated and recognized for all legal purposes.
Avoid Informal Agreements:
- Personal agreements or informal separations have no legal effect on the voiding or annulling of the marriage. A judicial decree is mandatory.

9. Conclusion

In the Philippines, marriage is strictly regulated to protect minors and preserve the sanctity of married life. Marriages involving individuals below 18 years old are void ab initio, and they require a court-issued judicial declaration of nullity for any future legal clarity (including the ability to remarry). Conversely, marriages contracted by parties aged 18 to 20 without parental consent are voidable and must be formally annulled within the legal time limits set by the Family Code.

Given the nuanced legal distinctions, the procedural steps, and the long-term consequences on property relations and children’s legitimacy, anyone facing these legal issues is advised to seek professional legal assistance. The law’s overarching intent is to prevent child exploitation, ensure due process, and protect all parties—especially minors—from the lifelong implications of invalid or voidable marriages.