ISAI: The Transfer Tax You’ll Pay When You Buy Property in La Paz, Mexico

Every buyer I work with eventually asks about the same line item on their closing statement: ISAI. It’s usually the single biggest number on the list – bigger than the notario’s fee, bigger than the registry charges – and it catches people off guard because nobody mentioned it back when they were just browsing listings.

ISAI stands for Impuesto Sobre Adquisicion de Inmuebles, roughly “tax on the acquisition of real property.” It’s a one-time transfer tax that states and municipalities across Mexico charge when a property changes hands, and Baja California Sur is no exception. The idea is simple: the government taxes the transfer itself, separate from the ongoing property tax, predial, you’ll pay every year after you own the place.

Who actually calculates and collects it

You don’t write a separate check to a tax office for this one. The notario publico handling your purchase calculates ISAI as part of closing, collects it along with the rest of the closing funds, and pays it to the state before your escritura (the deed) gets registered. It’s built into the closing cost estimate your notario gives you before you sign anything, so it shouldn’t show up as a surprise bill after the fact, as long as you’ve budgeted for closing costs properly going in.

How the amount gets set

This is the part I can’t give you an exact number on, and I’d be doing you a disservice if I made one up. ISAI rates are set at the state and municipal level, they get adjusted from time to time, and the base it’s calculated against isn’t always simply “the price you paid.” Notarios typically calculate it against whichever is higher: the purchase price on your contract, or the property’s official appraised value on file with the municipality. That second part matters more than people expect, especially on a property that hasn’t changed hands in years and may be carrying an outdated appraised value.

Because the rate and the calculation method can both move, I tell every buyer the same thing: ask your notario for the current ISAI figure as part of your closing cost estimate before you make an offer, not after. That’s a quick call for them, and it turns a vague worry into an actual number you can plan around.

Where it fits into your total closing costs

I quote buyers a closing cost of around 5 percent of the purchase price for a typical transaction in La Paz, Mexico, and ISAI is usually the largest single piece of that total – bigger than the notario’s own fee or the registration charges. If you’ve already read my post on what closing costs actually look like in La Paz, ISAI is the tax piece inside that range, not something extra stacked on top of it. The same estimate that includes ISAI also covers the notario’s fee, the registration charges, and the fideicomiso setup if you’re buying through a bank trust.

If you’re buying land in La Ventana or El Sargento

If you’re buying land rather than a built home, ask your notario to confirm how ISAI will be calculated on that specific parcel before you make an offer. Which number the tax gets based on, the contract price or the appraised value on file, isn’t always obvious up front on a lot that hasn’t traded hands in a while, and it’s worth knowing before you commit. I build that confirmation into every land offer I put together.

What I tell buyers

ISAI isn’t something to be afraid of. It’s a normal, expected part of buying property anywhere in Mexico, La Paz included. The mistake I see buyers make is not budgeting for it because nobody told them it existed until they were looking at a closing statement. When I put together a purchase offer for a client, I build a closing cost estimate into the numbers from the start, confirm it with the notario once we’re under contract, and make sure there are no surprises waiting at the closing table.

If you’re starting to look seriously at property in La Paz, La Ventana, or El Sargento, Mexico, I’m happy to walk you through what your actual closing costs, ISAI included, would look like on a specific property before you ever make an offer. Email me or call +52 612-111-3604 and I’ll put real numbers in front of you, free of charge.

Search current buyer resources, browse La Paz homes for sale, La Ventana listings, or El Sargento listings at SearchBajaHomes.com.

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