If you are an American selling real estate in Mexico, you will owe capital gains tax to both Mexico and the United States. Mexico calls this tax ISR (Impuesto Sobre la Renta), and for non-resident sellers, the notario publico handling your closing will withhold either a flat 25% of the gross sale price or between 1.92% and 35% of your net gain, depending on which calculation method you elect. You can then claim a Foreign Tax Credit on your US return to avoid being taxed twice on the same gain. Understanding exactly how these two tax systems interact is the difference between an unpleasant surprise at closing and a well-planned exit that keeps more money in your pocket.
This guide walks through the entire capital gains tax picture for Americans selling property in Los Cabos and elsewhere in Mexico, including the Mexican ISR calculation, the notario's withholding role, deductible expenses, the US side of the equation, a worked example on a $2.5 million sale, and legal strategies to reduce your liability.
What Is ISR (Capital Gains Tax) in Mexico?
In Mexico, capital gains on real estate sales fall under the Impuesto Sobre la Renta (ISR), which translates literally to "Income Tax." The ISR is governed by Mexico's Ley del Impuesto Sobre la Renta (Income Tax Law), administered by the Servicio de Administracion Tributaria (SAT), Mexico's equivalent of the IRS.
When you sell a property, the gain (the difference between your adjusted purchase price and your sale price) is treated as taxable income. Mexico does not have a separate "capital gains tax" category the way some countries do. Instead, capital gains from real estate are folded into the income tax framework, which is why you will see Mexican tax professionals refer to it simply as ISR.
There is one important exemption worth knowing: Mexican residents who sell their primary residence can exclude gains up to approximately 700,000 UDIs (Unidades de Inversion, an inflation-indexed unit) from ISR, which as of 2026 equals roughly 5.6 million Mexican pesos (around $310,000 USD), according to Mexico's SAT guidelines and the Banco de Mexico UDI valuation [1]. However, this exemption applies only once every three years and only to properties used as a primary home. As an American who owns vacation or investment property in Mexico through a fideicomiso (bank trust), you almost certainly will not qualify for this exemption.
Tax Rates for Foreign Sellers (Non-Residents)
Non-resident sellers in Mexico face two calculation methods for ISR on real estate sales. Your notario publico will calculate both and, in practice, apply whichever results in the lower tax, provided you furnish adequate documentation of your original purchase price and deductible expenses.
Option 1: The Flat Rate (25% of Gross Sale Price)
Under Article 126 of Mexico's Income Tax Law, the notario may withhold a flat 25% of the total sale price (not the gain, the entire sale price) when the seller cannot document the original acquisition cost [2]. This is the worst-case scenario and almost always results in a significantly higher tax bill. It exists as a default for sellers who lack paperwork proving what they paid for the property.
Option 2: The Progressive Rate (1.92% to 35% of Net Gain)
If you can document your original purchase price (the escritura publica from when you bought the property) along with qualifying deductible expenses, the gain is calculated as net profit and taxed using Mexico's progressive income tax brackets. According to SAT's published tax tables for 2025-2026, the rates are [3]:
| Taxable Net Gain (MXN) | Marginal Rate |
|---|---|
| Up to $8,952 | 1.92% |
| $8,953 - $75,984 | 6.40% |
| $75,985 - $133,536 | 10.88% |
| $133,537 - $155,229 | 16.00% |
| $155,230 - $185,852 | 17.92% |
| $185,853 - $374,837 | 21.36% |
| $374,838 - $590,796 | 23.52% |
| $590,797 - $1,127,926 | 30.00% |
| $1,127,927 - $1,503,902 | 32.00% |
| $1,503,903 - $4,511,707 | 34.00% |
| Over $4,511,707 | 35.00% |
For luxury real estate in Los Cabos, where sales prices commonly exceed $1 million USD, the gain almost always falls into the 30% to 35% marginal bracket. However, because the rate is applied to the net gain (not the gross sale price), the effective tax rate is dramatically lower than the flat 25%-of-gross alternative.
This is why documentation is everything. Keeping your original escritura, receipts for improvements, and records of closing costs from when you purchased the property is not optional -- it is the single most important thing you can do to reduce your Mexican tax liability when you eventually sell.
The Notario's Role in Tax Withholding
In Mexico, the notario publico is far more than a notary in the American sense. A notario is a government-appointed legal officer who authenticates real estate transactions, ensures tax compliance, and serves as the withholding agent for ISR on behalf of SAT.
Here is what the notario does regarding your capital gains tax:
- Calculates the ISR using both methods (flat rate and progressive rate), applying the lower amount if documentation supports it.
- Inflation-adjusts your purchase price using the Indice Nacional de Precios al Consumidor (INPC) published by INEGI (Mexico's statistics agency). This adjustment increases your cost basis to account for inflation between your purchase date and sale date, reducing your taxable gain [4].
- Withholds the ISR from the sale proceeds before disbursing the net amount to you. This is not optional. The notario is legally obligated to withhold and remit the tax to SAT.
- Issues a constancia de retenciones (withholding certificate) documenting exactly how much ISR was withheld. You will need this document for your US tax return.
- Files the tax payment with SAT within 15 business days of the transaction.
Because the notario calculates and withholds the tax at closing, you do not need to file a separate Mexican tax return for the capital gains on the sale (assuming it is your only Mexican-source income for the year). The withholding is considered a final payment. However, it is strongly advisable to have a Mexican tax accountant (contador) review the notario's calculation before closing to ensure accuracy, particularly on high-value transactions in the $1 million+ range common in Los Cabos luxury communities.
Deductible Expenses That Reduce Your Tax Basis
The difference between your inflation-adjusted acquisition cost and the sale price is your gross gain. But you can reduce that gain further by deducting qualifying expenses. Under Mexico's Income Tax Law (Articles 121 and 123), the following expenses are deductible when calculating ISR on real estate sales [2]:
- Original acquisition costs: What you paid for the property, as stated in your escritura publica, adjusted for inflation via INPC.
- Capital improvements: Construction, remodeling, and additions -- but only if you have facturas (official Mexican tax invoices, now called CFDI). Informal receipts or cash payments to contractors without facturas are not deductible.
- Notario fees at purchase: The fees you paid your notario when you originally acquired the property.
- Acquisition tax (ISAI): The Impuesto Sobre Adquisicion de Inmuebles you paid at purchase (typically 2% of the assessed value in Baja California Sur, per BCS state tax law) [5].
- Real estate commissions: Commissions paid to licensed real estate agents on the sale, supported by facturas.
- Appraisal fees: If required for the transaction.
- Fideicomiso setup and annual fees: The fees paid to establish and maintain your bank trust may be deductible if properly documented with facturas.
Key requirement: Every deductible expense must be backed by a CFDI (Comprobante Fiscal Digital por Internet) -- Mexico's official electronic invoice. If your contractor gave you a handwritten receipt, it does not count. This is the most common mistake American sellers make: spending $200,000 on a kitchen renovation but having no deductible expense to show for it because they paid cash without requesting facturas.
US Tax Implications: Avoiding Double Taxation
As a US citizen or resident, you are taxed on worldwide income, including capital gains on foreign real estate. However, the US-Mexico Tax Treaty and the Foreign Tax Credit mechanism exist specifically to prevent you from paying full tax to both countries on the same gain [6].
Step 1: Report the Sale on Your US Return
You must report the sale of your Mexican property on your US federal tax return. The gain is calculated using US rules, which differ from Mexico's calculation in several ways:
- The US uses your original cost basis in USD (converted at the exchange rate on the date you purchased the property), not the INPC-adjusted peso amount.
- The sale price is converted to USD at the exchange rate on the closing date.
- US long-term capital gains rates apply if you held the property for more than one year: 0%, 15%, or 20% depending on your taxable income, plus a potential 3.8% Net Investment Income Tax (NIIT) for high earners, per IRS guidelines [7].
Step 2: Claim the Foreign Tax Credit (Form 1116)
The ISR withheld by the Mexican notario qualifies as a creditable foreign tax under IRS rules. You claim this credit on Form 1116 (Foreign Tax Credit), which reduces your US tax liability dollar-for-dollar by the amount of Mexican tax you already paid [8].
In many cases, particularly for luxury property sales in Los Cabos, the Mexican ISR (calculated at progressive rates up to 35%) exceeds the US capital gains tax (typically 20% + 3.8% NIIT = 23.8% for high-income taxpayers). When this happens, the Foreign Tax Credit fully eliminates your US tax on the gain, and you may even have excess credits that can be carried forward for up to 10 years.
Step 3: FBAR and FATCA Compliance
If at any point during the year the aggregate balance in your foreign financial accounts exceeds $10,000, you must file FinCEN Form 114 (FBAR) [9]. This can be triggered if your Mexican closing proceeds are held temporarily in a Mexican bank account, or if you maintain a Mexican bank account for property tax payments and utilities.
Additionally, under FATCA (Foreign Account Tax Compliance Act), certain US taxpayers with foreign financial assets exceeding $50,000 on the last day of the year (or $75,000 at any point during the year for single filers) must file Form 8938 with their tax return [10]. Real property held directly is not a reportable asset under FATCA, but financial accounts used in connection with the property may be.
The penalties for failing to file FBAR can reach $10,000 per violation for non-willful violations and up to the greater of $100,000 or 50% of the account balance for willful violations, according to FinCEN enforcement guidelines [9]. Do not overlook these filing requirements.
Worked Example: $2.5M Sale on a Property Purchased at $1.5M
Let us walk through a realistic scenario for a luxury property sale in the Los Cabos Corridor.
The Facts
- Purchase price (2019): $1,500,000 USD (documented in escritura publica)
- Sale price (2026): $2,500,000 USD
- Documented improvements: $150,000 USD (kitchen and pool renovation, with CFDIs)
- Original closing costs (notario + ISAI): $60,000 USD
- Fideicomiso setup and annual fees (7 years): $12,000 USD
- Real estate commission on sale (5%): $125,000 USD
- Exchange rate at purchase: 19.2 MXN/USD
- Exchange rate at sale: 18.0 MXN/USD
- INPC inflation factor (2019-2026): approximately 1.38 (per INEGI published indices) [4]
Mexican ISR Calculation (Progressive Method)
- Sale price in MXN: $2,500,000 x 18.0 = 45,000,000 MXN
- Original cost in MXN: $1,500,000 x 19.2 = 28,800,000 MXN
- Inflation-adjusted cost: 28,800,000 x 1.38 = 39,744,000 MXN
- Deductible expenses (in MXN, inflation-adjusted where applicable):
- Improvements: $150,000 x 19.5 (avg rate) x 1.20 (partial INPC) = 3,510,000 MXN
- Original closing costs: $60,000 x 19.2 x 1.38 = 1,589,760 MXN
- Fideicomiso fees: $12,000 x 18.5 (avg) = 222,000 MXN
- Sales commission: $125,000 x 18.0 = 2,250,000 MXN
- Total deductions: 7,571,760 MXN
- Taxable gain: 45,000,000 - 39,744,000 - 7,571,760 = -2,315,760 MXN
Wait -- in this scenario the inflation adjustment and deductions actually eliminate the Mexican taxable gain entirely. This is not uncommon when the peso weakens against the dollar between purchase and sale, and when inflation has been significant (Mexico's cumulative inflation from 2019 to 2026 has been approximately 38%, per INEGI data) [4].
Let us adjust the example to show a scenario where there IS a taxable gain, which is more common when the property has appreciated significantly in peso terms:
Adjusted Scenario (Higher Peso-Denominated Appreciation)
- Same facts, but assume the exchange rate at purchase was 18.5 MXN/USD (less favorable to buyer) and improvements were $80,000 USD with CFDIs
- Sale price in MXN: $2,500,000 x 18.0 = 45,000,000 MXN
- Original cost in MXN: $1,500,000 x 18.5 = 27,750,000 MXN
- Inflation-adjusted cost: 27,750,000 x 1.38 = 38,295,000 MXN
- Deductions:
- Improvements: 80,000 x 18.5 x 1.25 = 1,850,000 MXN
- Original closing costs: 60,000 x 18.5 x 1.38 = 1,531,800 MXN
- Fideicomiso fees: 222,000 MXN
- Sales commission: 2,250,000 MXN
- Total deductions: 5,853,800 MXN
- Taxable gain: 45,000,000 - 38,295,000 - 5,853,800 = 851,200 MXN (approximately $47,289 USD)
- ISR at progressive rates: On 851,200 MXN of gain, applying Mexico's progressive brackets, the tax falls primarily in the 30% bracket. Effective ISR: approximately 210,000 MXN ($11,667 USD)
Compare to Flat Rate Method
| Method | Tax Base | Tax Amount (MXN) | Tax Amount (USD) |
|---|---|---|---|
| Flat rate (25% of gross) | 45,000,000 MXN | 11,250,000 | $625,000 |
| Progressive rate (net gain) | 851,200 MXN | ~210,000 | ~$11,667 |
The difference is staggering: $625,000 vs $11,667. This is why documentation is not just recommended -- it is financially essential. Sellers who cannot prove their original acquisition cost face the flat 25% rate, which on a $2.5 million sale means over $600,000 in Mexican tax.
US Side of This Transaction
- US cost basis: $1,500,000 + $150,000 improvements + $60,000 closing costs = $1,710,000
- US sale price: $2,500,000 - $125,000 commission = $2,375,000
- US capital gain: $2,375,000 - $1,710,000 = $665,000
- US tax (20% LTCG + 3.8% NIIT): $665,000 x 23.8% = $158,270
- Foreign Tax Credit (ISR paid to Mexico): $11,667
- Net US tax owed: $158,270 - $11,667 = $146,603
- Total combined tax (Mexico + US): $11,667 + $146,603 = $158,270
Notice that the total combined tax equals the US tax amount. The Foreign Tax Credit ensures you are not double-taxed: the Mexican tax reduces your US bill dollar-for-dollar. In cases where the Mexican ISR exceeds the US tax (which can happen with less favorable exchange rate scenarios or less documentation), you would owe zero to the US and carry the excess credit forward.
How to Minimize Your Tax Liability Legally
There are several legitimate strategies to reduce your capital gains tax exposure when selling property in Mexico:
1. Keep Every CFDI (Factura)
This is the single most impactful action. Every peso you spend on improvements, maintenance upgrades that add value, notario fees, and trust fees -- if it has a CFDI, it is deductible. If it does not have a CFDI, it does not exist for tax purposes. Start requesting facturas from day one of ownership.
2. Understand the INPC Inflation Adjustment
Mexico's inflation adjustment can substantially increase your cost basis. Between 2019 and 2026, cumulative inflation in Mexico has exceeded 38% according to INEGI data [4]. That means a property you bought for 28 million pesos automatically has an adjusted cost basis of roughly 38.6 million pesos before you even count deductible expenses. Work with your contador to ensure the notario applies this adjustment correctly.
3. Time Your Sale Strategically
Because Mexico calculates the gain in pesos, exchange rate fluctuations can significantly affect your tax. Selling when the peso is strong (fewer pesos per dollar) means your dollar-denominated sale price converts to fewer pesos, potentially reducing or eliminating your peso-denominated gain. Keep an eye on USD/MXN exchange rates as part of your exit strategy.
4. Allocate the Purchase Price Properly
If you purchased a furnished property or one with significant personal property (appliances, furniture, art), ensure the escritura properly allocates value between the real property and personal property. Personal property sold separately is not subject to the same ISR real estate rules and may reduce the taxable real estate transaction value.
5. Use a Cross-Border Tax Professional
This is not an area for DIY tax preparation. You need a Mexican contador who understands ISR on real estate transactions AND a US CPA or tax attorney who handles international tax and Form 1116. Many US-based CPAs with Mexico expertise work with Los Cabos clients. The cost of professional advice (typically $3,000 to $5,000 for both sides) is trivial compared to the potential tax savings on a million-dollar-plus transaction.
6. Consider a 1031 Exchange -- But Know the Limits
A US Section 1031 like-kind exchange allows you to defer US capital gains by reinvesting in another property. However, the Tax Cuts and Jobs Act of 2017 limited 1031 exchanges to domestic real property, meaning you cannot do a 1031 exchange from a Mexican property into a US property, or vice versa, per IRS guidance on Section 1031 [11]. A 1031 exchange from one Mexican property to another Mexican property is theoretically possible but extremely complex and rarely attempted in practice. Consult a tax attorney before pursuing this route.
7. Review Your Fideicomiso Structure
Your fideicomiso is the legal vehicle that holds your property in Mexico's restricted zone. Ensure that the trust document properly reflects all beneficiaries and that any change in beneficial interest (such as adding a spouse or transferring to an LLC) has been properly structured to avoid triggering an unintended taxable event. The annual fideicomiso fees you pay to the bank are also part of your deductible cost basis.
Frequently Asked Questions
How much is capital gains tax on property in Mexico for Americans?
It depends on whether you can document your original purchase price. If you can, the Mexican ISR is calculated on your net gain at progressive rates from 1.92% to 35%. If you cannot, the notario withholds a flat 25% of the gross sale price. On a $2 million sale with a well-documented $1.2 million purchase price, you might owe $10,000 to $50,000 in Mexican ISR after inflation adjustments and deductions. Without documentation, the flat rate would be $500,000. On the US side, you owe long-term capital gains tax (typically 15-23.8%) on the gain calculated in USD, minus a dollar-for-dollar credit for the Mexican tax paid.
Can I avoid paying capital gains tax in Mexico if I reinvest the proceeds?
Mexico does not have an equivalent of the US 1031 exchange for real estate. There is no legal mechanism to defer Mexican ISR by reinvesting in another Mexican property. The primary residence exemption (up to approximately 700,000 UDIs, per SAT guidelines) applies only to Mexican tax residents selling their primary home, and only once every three years [1]. For foreign sellers of vacation or investment property in Los Cabos, the ISR is due at closing with no deferral option.
What documents do I need to keep to reduce my capital gains tax in Mexico?
At minimum, you need: (1) your original escritura publica showing the purchase price, (2) CFDIs (facturas) for all capital improvements and renovations, (3) proof of notario fees and ISAI (acquisition tax) paid at purchase, (4) fideicomiso setup and annual maintenance fee receipts, and (5) any appraisal reports. All deductible expenses must be supported by official Mexican tax invoices (CFDI). Handwritten receipts, bank statements, and US-issued invoices are generally not accepted by the notario or SAT as proof of deductible expenses.
Do I have to file a Mexican tax return when I sell property?
Generally, no. For non-residents, the ISR withholding performed by the notario at closing is considered a definitive payment (pago definitivo), according to Article 126 of Mexico's Income Tax Law [2]. The notario calculates, withholds, and remits the tax to SAT on your behalf. You do not need to file a separate annual Mexican tax return for the capital gain unless you have other Mexican-source income. However, you must still report the sale and claim the Foreign Tax Credit on your US tax return using Form 1116.
What happens if the notario calculates my ISR incorrectly?
Errors do happen, particularly on complex transactions involving multiple improvements over many years. If the notario overstates your tax, you may be able to request a refund from SAT, but the process is bureaucratic and time-consuming (often 6-12 months or longer). The better approach is to have your own Mexican contador review the notario's preliminary calculation before closing. This independent review typically costs $500 to $1,500 and can save you tens of thousands of dollars. If there is a disagreement between your contador and the notario, it should be resolved before the escritura is signed.
The Bottom Line
Capital gains tax on Mexican real estate is not something to figure out at the closing table. The combination of Mexico's ISR and US federal capital gains tax creates a two-country tax obligation that requires advance planning. The good news: if you keep proper documentation (CFDIs for every improvement, your original escritura, fideicomiso records) and work with qualified cross-border tax professionals, the Mexican ISR on your net gain is often modest relative to the property's value. The inflation adjustment alone can significantly reduce your taxable gain in peso terms.
If you are considering buying luxury real estate in Los Cabos and already thinking about your eventual exit strategy -- which is exactly the right mindset -- we can connect you with trusted cross-border tax advisors, experienced notarios, and contadores who handle these transactions regularly. Understanding the tax picture before you buy makes the selling process years later dramatically simpler.
Sources
- Servicio de Administracion Tributaria (SAT), Mexico. "Enajenacion de bienes inmuebles -- Exencion para casa habitacion." sat.gob.mx. Banco de Mexico, UDI daily valuation tables.
- Ley del Impuesto Sobre la Renta (LISR), Articles 121, 123, 126. Diario Oficial de la Federacion, Mexico.
- SAT, "Tarifas para el calculo del ISR." Published annual tax tables, 2025-2026 fiscal year. sat.gob.mx.
- INEGI (Instituto Nacional de Estadistica y Geografia). "Indice Nacional de Precios al Consumidor (INPC)." Monthly published data series, 2019-2026. inegi.org.mx.
- Gobierno del Estado de Baja California Sur. "Ley de Hacienda del Estado de Baja California Sur" -- ISAI rates for property acquisitions.
- US-Mexico Tax Treaty (Convention Between the United States and Mexico for the Avoidance of Double Taxation), Article 13 (Capital Gains). irs.gov, Treaty documents.
- Internal Revenue Service. "Topic No. 409, Capital Gains and Losses" and "Net Investment Income Tax." irs.gov.
- Internal Revenue Service. "Form 1116, Foreign Tax Credit." Instructions and Publication 514, Foreign Tax Credit for Individuals. irs.gov.
- Financial Crimes Enforcement Network (FinCEN). "Report of Foreign Bank and Financial Accounts (FBAR)." FinCEN Form 114 instructions. fincen.gov.
- Internal Revenue Service. "Form 8938, Statement of Specified Foreign Financial Assets." FATCA filing thresholds. irs.gov.
- Internal Revenue Service. "Like-Kind Exchanges -- Real Estate Tax Tips." Section 1031, post-Tax Cuts and Jobs Act guidance. irs.gov.