Spanish has at least three verbs that are frequently used to indicate that something exists: haber, estar and existir. A few other verbs such as quedar are also used less frequently to indicate existence.

Most common for indicating mere existence is haber, which takes the special form hay in the indicativepresent tense in both singular and plural usage. Traditionally, singular forms are used for both singular and plural meaning in other tenses, although in current usage the plural forms are common.

• Hay una cosa que te quiero decir. (There is one thing I want to tell you.)
• La iglesia católica dice que hay tres personas divinas pero un solo Dios. (The Catholic church says there are three divine persons but a singular God.)
• Había un hombre que se llamaba Pablo. (There was a man named Pablo.)
• Si las personas fueran dinero, habría muchos billetes falsos. (If people were money, there would be a lot of counterfeit bills.)
• En un patio trasero había unas cuantas gallinas y 18 patas. (On a back patio there were a few hens and 18 ducks.)
• Siempre habrá un nuevo amanecer. (There will always be a new dawn.)

Note that while all of these sentences have been translated using "there + a form of 'to be,'" it would have also been possible to use various tenses of "to exist."

Haber cannot be used in this way when its subject is a specific person or thing, just as constructions such as "there is" or "there were" cannot be used in the English equivalent. In such cases, estar is typically used. So while we could say, "Hay muchas personas en China" (There are many people in China), we'd have to use estar when talking about specific people: Los oficiales del gobierno están en China.

(The government officials are in China.)

• No hay computadoras aquí. (There are no computers here.) Mi computadora no está aquí. (My computer isn't here.)
• Había pandillas cerca de la escuela. (There were gangs near the school.) Las pandillas de Arturo estaban cerca de la escuela. (Arturo's gangs were near the school.)
• Hay una chica en la clase que me gusta. (There is a girl in the class I like.) Me gusta Katrina, que está en la clase. (I like Katrina, who is in the class.)
• ¿Hay alguien en casa? (Is there anybody home?) ¿Está en casa tu madre? (Is your mother home?)

Existir can be used in nearly all situations where "exists" is suitable in English, although it also can be translated much as haber and estar are above. It is not unusual to place the subject of existir after the verb.

• No existe la persona perfecta. (The perfect person doesn't exist.)
• No existen límites. (There are no limits.)
• Los dinosaurios existieron y se extinguieron muchísimo tiempo antes del surgimiento de la especie humana. (Dinosaurs existed and went extinct a huge amount of time before the emergence of the human species.)
• Siempre van a existir los libros. (There will always be books.)

In certain contexts, a few other verbs can refer primarily to existence:

• ¡Solo quedan dos semanas! (There are only two weeks left!)
• En las profundidades del océano se hallan tesoros escondidos. In the depths of the ocean there are hidden treasures.
• En todas sus obras se hallan ideas profundas y originales. In all his works there are profound and original ideas.
• ¿En que país de Europa se encuentran los hombres mas guapos? (In which European country are there the most handsome men?)

Although ser (usually translated "to be") is often classified as an existential verb, it is almost never used to indicate mere existence, but rather to indicate qualities of persons or things. This can be seen in the typical translation of René Descartes' statement that "I think, therefore I am," where no form of ser is used: Pienso, luego existo.

Sources: Sample sentences have been adapted from sources that include Facebook conversations, espanol.answers.yahoo.com, La Prensa Gráfica (El Salvador), Armando Manzanero, Misdeberes.es, Sobrehistoria.com, Vamos a La Plata, Dibujos.net, SerPadres and Mariano Carderera.