Purchase option or arras: the difference in a Barcelona transaction

Arras and a purchase option (opción de compra) are different legal arrangements. Confusing them during price negotiations is a mistake that can later prove expensive for one party.

Both are based on freedom of contract under the Código Civil: the law does not rigidly prescribe their terms, which the parties shape themselves. This is why the distinction needs to be understood before signing, rather than assuming an option is 'roughly the same as a deposit'.

How an option differs from arras

Arras is a deposit agreement that creates a mutual commitment: both parties must complete the transaction, or may withdraw with compensation, depending on the type of arras. A purchase option works differently. It gives its holder, usually the buyer, a unilateral right—but no obligation—to buy at an agreed price within a specified period. In return, the buyer pays the seller a premium (prima), which the seller generally keeps whether or not the buyer exercises the right. Arras binds both parties; an option binds only the seller.

That asymmetry explains the option's price. The seller takes the risk that the market rises during the option period but the buyer never exercises the right to purchase. The premium compensates for that risk; it is not a formality.

When an option is more useful than a deposit

An option is useful when the buyer needs time to finalise finance, conduct due diligence on a complex plot or development project, or await a permit decision, without committing to buy if something fails to come together. During this period, the seller is bound by the agreed price and deadline, and the buyer pays a premium for that right. If exercised, the premium is usually credited towards the purchase price. The law does not set its amount: the parties negotiate it freely.

Land Registry registration

To protect the holder against third parties, the option can be registered in the Registro de la Propiedad if it meets the requirements on price, exercise period—no more than 4 years for registration purposes—and specification of the premium under article 14 of the Reglamento Hipotecario. An unregistered option is effective between the parties, but does not guarantee protection if, for example, the seller breaches the agreement by selling to someone else.

Using an option in a land strategy

For land investment, an option is practical precisely because a building permit decision may take months or years, while paying the full land price before permission is obtained creates an unjustified risk. An option fixes the price and allows time to assess the project without requiring an immediate purchase. Read more about how it fits into the DNPI land strategy.