Future Subjunctive in Spanish

Overview

The future subjunctive (subjuntivo futuro) is an archaic verb form inherited from Latin that has virtually disappeared from everyday Spanish. You will not hear it in conversation, and you will rarely see it in modern writing. However, it survives in a handful of proverbs, set expressions, and legal texts, which is why understanding it matters at the C1 level.

The most famous example is the proverb Donde fueres, haz lo que vieres — the Spanish equivalent of "When in Rome, do as the Romans do." If you can recognize this form and understand its meaning, you have a valuable tool for appreciating classical Spanish literature and navigating formal legal language.

In modern Spanish, the functions once served by the future subjunctive have been taken over by the present subjunctive or the present indicative. This tense is a window into the history of the language rather than a tool for daily communication.

How It Works

Formation

The future subjunctive is formed from the third-person plural preterite stem (the same stem used for the imperfect subjunctive) plus specific endings.

Person	Ending	Hablar	Comer	Ir/Ser
yo	-re	hablare	comiere	fuere
tú	-res	hablares	comieres	fueres
él/ella/usted	-re	hablare	comiere	fuere
nosotros/as	-remos	habláremos	comiéremos	fuéremos
vosotros/as	-reis	hablareis	comiereis	fuereis
ellos/ellas/ustedes	-ren	hablaren	comieren	fueren

Irregular Stems

Since the future subjunctive shares its stem with the imperfect subjunctive, all the same irregularities apply:

Verb	Preterite 3rd pl.	Future Subjunctive Stem
tener	tuvieron	tuviere, tuvieres...
hacer	hicieron	hiciere, hicieres...
poder	pudieron	pudiere, pudieres...
decir	dijeron	dijere, dijeres...
venir	vinieron	viniere, vinieres...
querer	quisieron	quisiere, quisieres...

Where It Survives

Context	Example
Proverbs	Donde fueres, haz lo que vieres.
Set expressions	Sea lo que fuere. / Venga lo que viniere.
Legal texts	Si así lo hiciere, que Dios se lo premie.
Oaths and formulas	...y si no, que me lo demanden.

Modern Equivalents

Future Subjunctive	Modern Replacement
Donde fueres...	Donde vayas... (present subjunctive)
Si así lo hiciere...	Si así lo hace... (present indicative)
Sea lo que fuere	Sea lo que sea (present subjunctive)
El que quisiere...	El que quiera... (present subjunctive)

Examples in Context

Spanish	English	Note
Donde fueres, haz lo que vieres.	When in Rome, do as the Romans do.	Classic proverb
Sea lo que fuere.	Whatever it may be.	Set expression
Si así lo hiciere, que Dios se lo premie.	If he should do so, may God reward him.	Oath formula
Venga lo que viniere.	Come what may.	Set expression
El que matare a otro será castigado.	He who kills another shall be punished.	Legal language
Si alguno contraviniere esta disposición...	Should anyone contravene this provision...	Legal text
Adonde fueres, llevarás tu sombra.	Wherever you go, you'll carry your shadow.	Proverb
Lo que fuere, sonará.	What will be, will be. (Whatever happens will make itself known.)	Saying

Common Mistakes

Trying to Use the Future Subjunctive in Conversation

• Wrong (contextually): Cuando llegare, te llamaré.
• Right: Cuando llegue, te llamaré.
• Why: The future subjunctive is extinct in spoken Spanish. Always use the present subjunctive for future reference in subordinate clauses.

Confusing It with the Imperfect Subjunctive

• Wrong identification: Mistaking hablare for hablara (imperfect subjunctive).
• Right: Recognizing the -re ending as future subjunctive vs. the -ra ending as imperfect subjunctive.
• Why: The stems are identical; only the endings differ. The -re forms are future subjunctive, while -ra forms are imperfect subjunctive.

Modernizing Proverbs

• Wrong: Donde vayas, haz lo que veas. (when quoting the proverb)
• Right: Donde fueres, haz lo que vieres.
• Why: Proverbs are fixed expressions. Even though the future subjunctive is archaic, proverbs retain their original form. Modernizing them changes their character.

Usage Notes

The future subjunctive was fully productive in medieval and early modern Spanish (up through the 16th and 17th centuries). If you read Don Quijote or other Golden Age literature, you will encounter it regularly. By the 18th century, it had largely been replaced by the present subjunctive in everyday use.

In modern legal Spanish, particularly in the constitutions and legal codes of Spain and some Latin American countries, the future subjunctive still appears. Article 1 of some laws may read: El que contraviniere... (He who should contravene...). Legal reform movements have advocated for replacing these forms with modern equivalents, and newer legislation tends to avoid them.

Portuguese, unlike Spanish, has preserved the future subjunctive as a fully active tense. If you also study Portuguese, you will find this knowledge directly transferable and far more practically useful.

Practice Tips

• Memorize the key proverbs: Learn three or four proverbs that use the future subjunctive (Donde fueres..., Sea lo que fuere, Venga lo que viniere). These are the most likely places you will encounter this tense, and knowing them enriches your cultural knowledge.

• Read Golden Age excerpts: Look at short passages from Cervantes or other classical authors. Identify the future subjunctive forms and rewrite them using modern equivalents. This sharpens both your historical awareness and your command of the present subjunctive.

• Compare with the imperfect subjunctive: Write out the conjugation of a verb in both the imperfect subjunctive (-ra forms) and the future subjunctive (-re forms) side by side. Notice the shared stem and different endings. This makes recognition much easier.

Related Concepts

• Prerequisite: Present Subjunctive