Let me ask you something honest: when you got married, did you sign a prenuptial agreement? If you are like most Indonesian couples, the answer is no.
Maybe you thought it was unromantic. Maybe your family said it implied distrust. Maybe nobody told you it mattered.
But here is what I need you to understand: for decades, that decision was irreversible. Once you were married without a prenup, you were locked into joint marital property for life.
That is no longer true. The law has changed, and you and I need to talk about it.
The Old Regime: Article 29 Before the Revolution
Under the original text of Article 29(1) of the 1974 Marriage Law, a marriage agreement could only be made "at the time of or before the marriage is conducted." That phrase, "at the time of or before," was an absolute wall. If you walked into your marriage without a prenuptial agreement, you had no legal mechanism to create one afterwards. The door was shut, permanently.
Article 35(1) then ensured that all property acquired during the marriage automatically became harta bersama, joint marital property. No exceptions, no negotiation, no way out. Your income, your investments, your business growth, everything merged into an undivided pool belonging equally to both spouses. For many couples, this arrangement works perfectly well. But for others, particularly those in mixed marriages, those running businesses with significant liability exposure, or those whose circumstances simply changed over the years, the inability to restructure their property regime mid-marriage created genuine injustice.
The Agrarian Law Problem: When Marriage Costs You Your Land
Now let me show you where this rigidity became truly devastating. The 1960 Basic Agrarian Law, restricts land ownership based on nationality. Article 21(1) states clearly that only Indonesian citizens may hold Hak Milik (freehold title). Article 21(3) then delivers the blow: if an Indonesian citizen who holds freehold land subsequently "obtains" foreign nationality or, critically, holds the land as part of joint property that includes a foreign national, that right must be relinquished within one year. Similarly, Article 36(1) restricts Hak Guna Bangunan (right to build) to Indonesian citizens and Indonesian legal entities.
Here is what this meant in practice: if you were an Indonesian citizen who married a foreign spouse without a prenuptial agreement, your land, purchased with your own money, before or during the marriage, was suddenly at risk. Because under Article 35 of the Marriage Law, all marital assets become joint property, and because your foreign spouse now had an undivided interest in that property, Article 21(3) of the Basic Agrarian Law required you to divest within one year. You could lose your own home because of a legal technicality you never knew existed.
For years, thousands of Indonesian citizens in mixed marriages faced this impossible situation. They could not retroactively create a prenup. They could not separate their property. They were trapped between two laws that, combined, stripped them of constitutional rights.
The Constitutional Court Steps In: Decision No. 69/PUU-XIII/2015
In 2016, everything changed. An Indonesian citizen married to a foreign national, challenged the constitutionality of Article 29(1), (3), and (4) of the Marriage Law and Articles 21(1), 21(3), and 36(1) of the UUPA before the Constitutional Court. Her argument was straightforward: these provisions, read together, violated her constitutional rights to equal treatment before the law (Article 28D(1) of the Constitution), freedom of choice (Article 28E(1)), and the right to own property (Article 28H(4)).
On 27 October 2016, the Constitutional Court issued Decision No. 69/PUU-XIII/2015, and it was revolutionary. The Court declared that Article 29(1) of the Marriage Law must now be read as: "At the time of, before, or during the course of the marriage, both parties by mutual agreement may enter into a written agreement, after which the content shall also apply to third parties insofar as such third parties are involved."
Let that sink in. The Court did not merely tweak a procedural rule. It fundamentally expanded the freedom of contract within marriage. For the first time in Indonesian legal history, you and your spouse can create a postnuptial agreement, a binding legal document that separates your property, restructures your financial relationship, or protects specific assets, at any point during your marriage. The agreement takes effect from the moment it is ratified and cannot disadvantage third parties.
What About Muslim Couples? The KHI Perspective
If you are Muslim, you might wonder whether this applies to you. The Islamic Compilation Law addresses marriage agreements in Articles 45 through 52. Article 45 permits spouses to enter into a ta'lik talak or other marriage agreement, while Article 47 states that during the marriage, the agreement may be revoked by mutual consent. The KHI's treatment of marital property under Articles 85 through 97 is broadly similar to the Marriage Law: harta bersama exists alongside individual property.
The Constitutional Court's decision, as a matter of constitutional interpretation, applies universally. It does not distinguish between Muslim and non-Muslim marriages. Therefore, Muslim couples who previously had no prenup can now execute a postnuptial agreement to separate their property. This has practical significance under the KHI's inheritance provisions (Articles 171-193), because it allows spouses to clearly delineate which assets constitute individual property (and thus fall entirely into their estate upon death) versus joint property (which is halved before inheritance distribution).
Why Your Old Prenup Might Not Be Enough Either
Here is something else I want you to consider.
Even if you did sign a prenup years ago, life changes. You may have started a business since then. You may have acquired property that your original agreement did not contemplate. You may have children with special needs who require protected assets.
The postnup is not only for those who forgot to get a prenup. It is for anyone whose circumstances have evolved beyond what their original agreement, or lack thereof, can accommodate.
The Practical Path Forward
After the Constitutional Court's ruling, the mechanism is clear. You and your spouse can visit a lawyer specialized in family law like Wijaya & Co., draft a postnuptial agreement separating some or all of your assets, have it ratified, and register it.
For mixed-marriage couples, this immediately resolves the UUPA problem: once your property is legally separated from joint ownership, your Indonesian-citizen land rights are secure. For business owners, it shields personal assets from commercial liability. For couples approaching estate planning, it creates clarity about what belongs to whom before inheritance law applies.
The Warning I Want to Leave You With
The Constitutional Court gave us this tool in 2016. That was nearly ten years ago. Yet most Indonesian couples still do not know postnuptial agreements exist, let alone that they are constitutionally guaranteed. If you are in a mixed marriage and still holding land as joint property, you are living on borrowed time under Article 21(3) of the UUPA. If you are running a business without asset separation, your spouse's debts could consume your earnings and vice versa.
Your prenup is obsolete, or perhaps you never had one. Either way, the postnup is not a sign of distrust. It is a sign of maturity. It is you and your spouse sitting down and saying: we choose to organise our financial lives deliberately, rather than leaving it to a default formula that was never designed for us. The law finally caught up. Now it is your turn.
My name is Asep Wijaya, writing for Wijaya & Co. We orchestrate to assist you navigate. Thank you for reading my posts.