Conjugating the Irregular Spanish Verb Ser (to Be)

Spanish verbs fall into different groups, and each group is conjugated a little differently. If you’re going to master Spanish verbs like ser, you need to be able to identify which group a verb belongs to: regular (follows regular conjugation rules for -ar, -er, and -ir verbs), stem-changing (morphs depending on how you use it in a sentence), spelling-changing (has consonant-spelling changes in some forms to follow pronunciation rules), or reflexive (reflects the action back on the subject of the sentence).
But then there are those verbs that refuse to be lumped into a category: the irregulars. Ser (sehr) (to be) is an irregular -er verb; it doesn’t follow most normal ending patterns, so your best bet is to just memorize its conjugations. Other popular irregular Spanish verbs include estar, leer, tener, querer.
The present tense of ser
Here is the Spanish verb ser in the present tense:

Conjugation                                        Translation
yo soy                                                    I am
tú eres                                                   You (informal) are
él/ella/ello/uno es                             He/she/one is
usted es                                                You (formal) are
nosotros somos                                  We are
vosotros sois                                        You all (informal) are
ellos/ellas son                                     They are
ustedes son                                          You all (formal) are

The following examples show you ser in action:

La boda es el veintisiete de junio. (The wedding is the 27th of June.)
Ellos son mis abuelos. (They are my grandparents.)
The preterit tense of ser
The following table shows you ser at work in the preterit tense.
Conjugation                                           Translation
yo fui                                                       I was
tú fuiste                                                  You (informal) were
él/ella/ello/uno fue                             He/she/one was
usted fue                                                You (formal) were
nosotros fuimos                                   We were
vosotros fuisteis                                   You all (informal) were
ellos/ellas fueron                                They were
ustedes fueron                                    You all (formal) were

You use the preterit tense like this:
Fuimos al baile anoche. (We went to the dance last night.)
Fui a verte en tu casa. (I went to see you at your house.)
Think you’ve seen these conjugations before? You probably have; it just so happens that they’re also the preterit forms of the verb ir (to go). It may be confusing, but look on the bright side: It’s one fewer set of verbs you have to memorize.
The imperfect tense of ser
Ser is one of only three irregular imperfect verbs. Here’s that conjugation; notice that, like regular verbs, the first-person and third-person singular forms (yo and usted) are the same.
Conjugation                                                 Translation
yo era                                                           I used to be
tú eras                                                         You (informal) used to be
él/ella/ello/uno era                                 He/she/one used to be
usted era You (formal)                           used to be
nosotros éramos                                      We used to be
vosotros erais                                          You all (informal) used to be
ellos/ellas eran                                       They used to be
ustedes eran                                            You all (formal) used to be
Here are some examples of the imperfect tense:
Eramos futbolistas. (We used to be soccer players.)
Shakespeare era un gran escritor. (Shakespeare was a great writer.)
The future tense of ser
Good news! Ser is regular in the future tense, so you can apply the regular verb endings here.
Conjugation                                                      Translation
yo seré                                                                 I will be
tú serás                                                                You (informal) will be
él/ella/ello/uno será                                        He/she/one will be
usted será                                                            You (formal) will be
nosotros seremos                                              We will be
vosotros seréis                                                  You all (informal) will be
ellos/ellas serán                                                They will be
ustedes serán                                                    You all (formal) will be
The following samples put the future tense to work:
María sera una gran bailarina. (Maria will be a great dancer.)
Ustedes serán bienvenidos. (You will be welcome.)