It’s not necessary to have a Mexican will to purchase a property in San Miguel de Allende. However we highly recommend obtaining a Mexican will soon after you purchase. 

If a property owner dies without a Mexican will, it can take months or years of costly legal work to probate the property so that the heirs can receive the title in their name(s). If the property owner has a Mexican will, the process is reduced to a few weeks or months, depending on the situation. 

It’s important to note that a will from another country will not apply to your property in Mexico unless it has been translated and apostilled, and even then, the process of the will going through the Mexican courts will be longer than if the will was created in Mexico.