Spanish has a future subjunctive (futuro de subjuntivo) that you will almost never hear in modern conversation. Four centuries ago it was a productive tense, but today it survives mainly in legal language, a handful of proverbs, and a few frozen expressions. It's worth recognizing, even though you don't need to produce it in everyday speech.
If you have studied the imperfect subjunctive, the future subjunctive will look very familiar — they share the same stem and even most of the same letters.
Formation
The future subjunctive is built on the same stem as the imperfect subjunctive — the third person plural of the preterite, minus the final -ron. Instead of adding the usual -ra or -se endings, you add -re endings.
| Subject | hablar | comer | vivir |
|---|---|---|---|
| yo | hablare | comiere | viviere |
| tú | hablares | comieres | vivieres |
| él / ella / usted | hablare | comiere | viviere |
| nosotros | habláremos | comiéremos | viviéremos |
| ellos / ustedes | hablaren | comieren | vivieren |
Irregular preterites carry their irregularity over: tener → tuvieron → tuviere, ser/ir → fueron → fuere, decir → dijeron → dijere, haber → hubieron → hubiere.
There is also a compound future subjunctive (hubiere + past participle), used in the same contexts but for actions imagined as completed at a future point.
Why it became archaic
A bit of historical context helps explain why this tense fell out of use.
In classical Spanish, the future subjunctive was used after si, cuando, mientras, donde, and similar words whenever the action was hypothetical and set in the future: "Si lloviere mañana, nos quedaremos en casa."
Over time, Spanish speakers simplified the system by using the present subjunctive for those contexts (cuando llueva, mientras haya tiempo), and the present indicative after si (si llueve). By the early 1900s the future subjunctive had effectively dropped out of speech. Modern speakers understand it when they read it, but do not produce it.
Where it still lives
Legal and administrative texts
You will see the future subjunctive in constitutions, contracts, laws, and regulations, where archaic forms add weight and precision.
El que matare a otro será castigado conforme a la ley.
Whoever kills another shall be punished according to the law.
Si alguno de los herederos falleciere antes del reparto, su parte pasará a sus descendientes.
If any of the heirs dies before the distribution, their share shall pass to their descendants.
Proverbs and sayings
Several classic refranes preserve the future subjunctive:
Adonde fueres, haz lo que vieres.
When in Rome, do as the Romans do. (Wherever you go, do what you see.)
Sea lo que fuere, lo aceptaré.
Whatever it may be, I'll accept it.
Frozen expressions
A few set phrases keep the future subjunctive alive in ordinary speech. The most famous is "sea lo que fuere" ("whatever it may be" / "come what may"), still used for dramatic effect.
Venga lo que viniere, seguiré adelante.
Come what may, I'll keep going.
Pase lo que pasare, te apoyaré.
Whatever happens, I'll support you.
You can hear an echo of the future subjunctive in the more common modern construction "sea lo que sea" (with the present subjunctive). That phrase has completely replaced "sea lo que fuere" in everyday conversation.
A side-by-side with the imperfect subjunctive
The future subjunctive looks almost identical to the imperfect subjunctive -ra form — the only difference is the final vowel.
| Imperfect | Future |
|---|---|
| hablara | hablare |
| tuviera | tuviere |
| fuera | fuere |
If you mistake one for the other in a legal text, the meaning is usually still recoverable from context.
What to use instead today
Outside of the contexts above, the future subjunctive has been replaced by the present subjunctive:
| Archaic | Modern |
|---|---|
| cuando llegare | cuando llegue |
| si tuviere tiempo | si tengo tiempo |
| mientras viviere | mientras viva |
| donde estuviere | donde esté |
| como dijere la ley | como diga la ley |
For si-clauses about the future specifically, modern Spanish uses the present indicative, not the subjunctive: "Si llueve mañana", not "Si llueva mañana". See Conditionals: Type 1 for the modern pattern.
Recognition checklist
If you spot any of these endings on a verb in a formal text, you are looking at the future subjunctive:
| Ending | Subject |
|---|---|
| -are / -iere | yo, él, ella, usted |
| -ares / -ieres | tú |
| -áremos / -iéremos | nosotros |
| -aren / -ieren | ellos, ellas, ustedes |
These look almost identical to imperfect subjunctive -ra forms, but the -re ending is the giveaway: hablara (imperfect) vs. hablare (future).
Why bother learning it at all?
Three good reasons:
- Reading comprehension. Anyone who plans to read older Spanish literature, the Bible in Spanish, or legal documents will run into the future subjunctive. Recognizing it on sight saves you from confusion.
- Constitutional and contractual texts. Latin American constitutions are full of forms like "el que cometiere", "si la asamblea decidiere". If you ever need to read or translate them, knowing this tense is essential.
- A clearer picture of the system. Seeing the future subjunctive helps you understand why the present subjunctive llegue and the imperfect subjunctive llegara both exist — there used to be a third member, llegare, that has dropped out.
Modern parallels
When you encounter a future-subjunctive form, it almost always corresponds to a present-subjunctive form in modern usage. Mentally swap fuere → sea, tuviere → tenga, llegare → llegue and the meaning becomes obvious.
For everything you actually need in daily Spanish, stay with the present, imperfect, and pluperfect subjunctive — see Sequence of Tenses for how those work together, and review the present subjunctive triggers and imperfect subjunctive -ra forms that have replaced this archaic tense.
Related Topics
- Imperfect Subjunctive: -Ra FormsB2 — Learn how to form the imperfect subjunctive using the -ra endings, the most common form in Latin American Spanish.
- Subjunctive Triggers OverviewB1 — An overview of the WEIRDO categories that introduce the subjunctive in Spanish dependent clauses.
- Sequence of TensesC1 — How the tense of the main clause decides which subjunctive tense belongs in the subordinate clause.