The future subjunctive is supposed to be used in Spanish when a verb
or expression requiring the subjunctive in the main clause is in the
present or future and refers to a future action.
However, the future subjunctive is becoming obsolete. You are
unlikely to ever hear it, as in spoken Spanish it tends to be
replaced by the present subjunctive.
The Spanish future subjunctive may still be found in writing, such
as literature and and legal documents, so it's good to be able to
Conjugating the Spanish Future Subjunctive
The future subjunctive is conjugated much
like the -RA form of the imperfect
subjunctive: take the third person plural preterite
form of any regular, irregular, or stem-changing verb, drop the -RON ending to
find the radical, and add the appropriate ending:
future subjunctive endings
The yo and él forms of the future subjunctive are identical.
In the nosotros form, an
acute accent ´ is added to the last vowel in the radical.