Future Subjunctive in Spanish

In Brief

The Spanish future subjunctive is an archaic verb form now found chiefly in legal language, proverbs, and fixed expressions: sea lo que fuere (“whatever it may be”). Modern Spanish normally uses the present subjunctive instead: older cuando viniere corresponds to modern cuando venga. Most learners need to recognize this tense rather than use it freely.

Overview

The subjunctive is a verb mood (a set of forms that presents an event as desired, uncertain, conditional, or otherwise not simply asserted as fact). Spanish once had a dedicated future subjunctive for an uncertain event expected after the present: forms such as cantare, comiere, and viviere. It developed historically from Latin forms but is no longer part of ordinary conversation or neutral modern prose.

At C1, the practical goal is reading competence. You may encounter the future subjunctive in laws, contracts, administrative documents, older literature, proverbs, and intentionally traditional phrasing. A few expressions remain familiar even to speakers who would never create a new future-subjunctive sentence in daily life: sea lo que fuere and venga lo que viniere are good examples.

English has no directly matching everyday tense. Translations often use a present form, “may,” “should,” “shall,” or an indefinite construction such as “whoever.” Do not let the word future suggest the ordinary Spanish future indicative (cantará). The future subjunctive expresses a possible or unspecified future circumstance, not a prediction presented as fact.

How It Works

Forming the simple future subjunctive

Use the third-person plural form of the preterite (the completed simple past), remove -ron, and add the future-subjunctive endings. This is also the historical stem used by the imperfect subjunctive in -ra.

Preterite starting point	Remove -ron	Future subjunctive example	Meaning
hablaron	habla-	hablare	I/he/she should speak; may speak
comieron	comie-	comiere	I/he/she should eat; may eat
vivieron	vivie-	viviere	I/he/she should live; may live
fueron	fue-	fuere	I/he/she should be/go; may be/go
hicieron	hicie-	hiciere	I/he/she should do; may do

The complete endings are -re, -res, -re, -remos, -reis, -ren. The first- and third-person singular forms are identical. In the nosotros form, the stress is marked with a written accent.

Person	hablar	comer	vivir
yo	hablare	comiere	viviere
tú	hablares	comieres	vivieres
él, ella, usted	hablare	comiere	viviere
nosotros/as	habláremos	comiéremos	viviéremos
vosotros/as	hablareis	comiereis	viviereis
ellos, ellas, ustedes	hablaren	comieren	vivieren

Because the stem comes from the preterite, preterite irregularities remain:

Infinitive	Preterite they-form	Future subjunctive	Commonly encountered meaning
ser / ir	fueron	fuere	may be / may go
hacer	hicieron	hiciere	may do
venir	vinieron	viniere	may come
tener	tuvieron	tuviere	may have
decir	dijeron	dijere	may say
haber	hubieron	hubiere	may have; auxiliary form

Do not confuse -re and -ra

The future subjunctive resembles the -ra form of the imperfect subjunctive, but the two are not interchangeable endings:

Future subjunctive	Imperfect subjunctive	Modern contrast
si viniere	si viniera	old/formal possible future vs hypothetical or less likely condition
quien tuviere	quien tuviera	old/legal future holder vs hypothetical holder
cuando fuere	cuando fuera	old future circumstance vs past or hypothetical circumstance

In present-day neutral Spanish, an open future condition generally takes the present indicative after si: Si viene, hablaremos (“If he comes, we’ll talk”). Future time after cuando, quien, donde, or a similar connector commonly takes the present subjunctive: cuando venga, quien tenga, donde sea necesario.

The compound form: future perfect subjunctive

The future perfect subjunctive refers to something that will already have been completed. It consists of hubiere + past participle (the form such as hecho, “done,” used in compound tenses).

Person	haber	Example with hacer
yo	hubiere	hubiere hecho
tú	hubieres	hubieres hecho
él, ella, usted	hubiere	hubiere hecho
nosotros/as	hubiéremos	hubiéremos hecho
vosotros/as	hubiereis	hubiereis hecho
ellos, ellas, ustedes	hubieren	hubieren hecho

This compound tense remains especially recognizable in legal provisions: quien hubiere cometido el delito (“whoever has committed the offense”). Modern non-legal Spanish normally uses the present perfect subjunctive, quien haya cometido..., or recasts the sentence.

Examples in Context

Spanish	English	Note
Donde fueres, haz lo que vieres.	When in Rome, do as the Romans do.	Traditional proverb; literally, “Wherever you go, do what you see.”
Sea lo que fuere, debemos continuar.	Whatever it may be, we must continue.	Fixed expression combining present sea with future fuere.
Venga lo que viniere, no cambiaré de opinión.	Come what may, I will not change my mind.	Set, emphatic expression.
Si así lo hiciere, quedará obligado a comunicarlo.	Should he or she do so, they will be required to report it.	Legal or administrative style.
El que causare el daño responderá de sus consecuencias.	Whoever causes the damage shall be liable for its consequences.	An indefinite future person in legal language.
Cuando fuere necesario, se solicitará otro informe.	When necessary, another report will be requested.	Formal formula; modern Spanish prefers cuando sea necesario.
Quien tuviere interés legítimo podrá presentar una solicitud.	Anyone with a legitimate interest may submit an application.	Legal quien tuviere; modern quien tenga.
Adonde fueres, lleva contigo estos documentos.	Wherever you may go, take these documents with you.	Deliberately proverbial or elevated.
Cualquiera que dijere lo contrario deberá probarlo.	Anyone who says otherwise must prove it.	Archaic/formal; modern diga.
Los bienes que quedaren sin reclamar pasarán al Estado.	Any property left unclaimed shall pass to the state.	A possible future remainder.
Quien hubiere recibido el pago deberá emitir un recibo.	Whoever has received payment must issue a receipt.	Future perfect subjunctive.
Una vez hubieren concluido las actuaciones, se archivará el expediente.	Once the proceedings have concluded, the file will be closed.	Compound form in highly formal drafting.

These translations reproduce the meaning, not the Spanish morphology word for word. English “shall” may reflect legal style, while “whoever,” “anyone who,” and the ordinary present tense often provide a more natural equivalent.

Common Mistakes

Using it for every future event

• Wrong: Mañana trabajare desde casa.
• Right: Mañana trabajaré desde casa.
• Why: Trabajaré is the future indicative and makes a prediction or statement. Trabajare is an archaic subjunctive form and cannot replace it in an independent everyday sentence.

Treating old legal wording as normal conversation

• Unnatural today: Cuando viniere Marta, cenaremos.
• Natural today: Cuando venga Marta, cenaremos.
• Why: A future event after cuando takes the present subjunctive in modern Spanish. The older form may sound legalistic, literary, or jokingly grand.

Replacing a normal si condition with the future subjunctive

• Archaic/formal: Si tuviere alguna duda, consulte al secretario.
• Modern: Si tiene alguna duda, consulte al secretario.
• Why: In a real, open condition, present-day Spanish normally uses the present indicative after si. The future subjunctive survives in inherited formulas and some formal documents.

Substituting the future indicative in a fixed phrase

• Wrong: Sea lo que será.
• Right: Sea lo que fuere.
• Why: Será is future indicative, whereas this concessive formula (“whatever it may be”) preserves future subjunctive fuere. You may also hear sea lo que sea in ordinary modern Spanish.

Giving regular stems to irregular verbs

• Wrong: Si lo haciere...
• Right: Si lo hiciere...
• Why: Formation follows the preterite plural hicieron, not the infinitive hacer. Likewise: tuvieron → tuviere and dijeron → dijere.

Misreading hubiere as an ordinary future

• Wrong interpretation: quien hubiere firmado = “who will sign”
• Better interpretation: “whoever has signed / may have signed”
• Why: Hubiere firmado is future perfect subjunctive: the signing is complete before the legal consequence applies.

Usage Notes

The tense is obsolete in ordinary spoken Spanish, but obsolete does not mean incomprehensible or entirely absent. Set expressions remain available, and legal readers regularly meet forms such as fuere, hubiere, and resultare. A speaker may also use one playfully to imitate a solemn proclamation, an old story, or bureaucratic language.

Legal usage varies by country, institution, date, and drafting policy. Some modern legal writers retain the form because it has a long-established place in statutes; others replace it with the present indicative or present subjunctive for plainer style. Therefore, the presence of a future subjunctive is a strong register signal, but not proof that a text is ancient.

Proverbs preserve grammar the way English expressions preserve older wording. Learn Donde fueres, haz lo que vieres and sea lo que fuere as whole units first. That is more useful than trying to insert fuere or viniere into spontaneous speech.

Beyond the Basics: Meaning and Modern Replacements

The form commonly appears in subordinate clauses—clauses that depend on another part of the sentence—introduced by words such as si (“if”), cuando (“when”), quien (“whoever”), donde (“wherever”), or by a relative expression such as el que (“the one who”). The person or event is often not yet identified because the rule is meant to cover any future case.

There is no single mechanical replacement. Choose according to meaning:

Older or legal form	Typical modern form	Reason
cuando fuere necesario	cuando sea necesario	Future time after cuando takes present subjunctive.
quien tuviere derecho	quien tenga derecho	The future holder is indefinite.
si así lo hiciere	si así lo hace	A real/open si condition normally takes present indicative.
quien hubiere pagado	quien haya pagado	Completed action relevant to a future consequence.
si viniere mañana	si viene mañana	Modern open condition.

Do not automatically substitute the imperfect subjunctive. Si viniera mañana is fully modern, but it usually presents tomorrow’s arrival as hypothetical, tentative, or less likely. Si viene mañana is the neutral open condition. The lost future subjunctive once helped mark futurity and contingency together; modern Spanish distributes those meanings among several more common tenses.

Recognition becomes easier if you reverse the formation process. On seeing dijeren, mentally replace -re- with the familiar imperfect-subjunctive pattern and identify the preterite stem: dijeron → dije- → dijeren. Then use the connector and context to decide whether English needs “if,” “when,” “whoever,” “may,” or simply a present form.

Practice Tips

1. Build a recognition set from irregulars. Pair fueron–fuere, hicieron–hiciere, vinieron–viniere, tuvieron–tuviere, and dijeron–dijere. The preterite link makes unfamiliar forms predictable.
2. Modernize short sentences. Rewrite cuando fuere, quien tuviere, and si lo hiciere as cuando sea, quien tenga, and si lo hace. Explain why each replacement uses indicative or subjunctive.
3. Read for register, not production. In a law, contract, proverb collection, or older novel, highlight forms in -re and hubiere + participle. Ask what future condition they establish before translating them.

Related Concepts

• Prerequisite: Present Subjunctive — the modern form that replaces the future subjunctive in many subordinate clauses.