Irregular Verb in the Imperfect Tense Spanish | Key Patterns

Only three verbs change in the imperfect—ser, ir, and ver—while nearly every other verb follows steady -aba or -ía endings.

The imperfect tense is the past tense that helps you tell what was going on, what used to happen, and what a scene looked like. It’s the tense for “was doing,” “used to,” and “would (habitually).” If you’ve ever mixed it up with the preterite, you’re not alone. The good news: the imperfect is one of the most predictable verb forms in Spanish.

The part that trips people is the phrase “irregular verb.” In the imperfect, that label is almost boring—in a good way. There are only three irregular verbs you must memorize. Once you lock them in, the rest of the tense turns into pattern work: pick the right ending, then keep your accents straight.

What The Imperfect Tense Does In Real Spanish

Before you drill endings, get the feel of the tense. The imperfect doesn’t box an action into a finished event. It shows the action as ongoing, repeated, or simply true at that time.

Use The Imperfect For Ongoing Past Actions

Think of a past moment as a snapshot. The imperfect tells what was happening inside that snapshot.

• Leía cuando llamaste. (I was reading when you called.)
• Cocinábamos y sonaba música. (We were cooking and music was playing.)

Use The Imperfect For Habitual Past Routines

This is the “used to” use. It’s also the “would” use when “would” means a routine, not a single choice.

• De niño, jugaba en el parque. (As a kid, I used to play in the park.)
• Los domingos, íbamos a casa de mis abuelos. (On Sundays, we used to go to my grandparents’ house.)

Use The Imperfect For Background Details

Descriptions in the past often lean on the imperfect: weather, age, time, feelings, and setting.

• Era tarde y hacía frío. (It was late and it was cold.)
• Tenía veinte años. (I was twenty.)

If you want a formal definition, the Real Academia Española describes the imperfect as a past tense with imperfective aspect, centered on the unfolding of the situation rather than its start or end; see the RAE glosario entry for “pretérito imperfecto de indicativo”.

How To Form The Imperfect Endings Without Guessing

Imperfect endings are tied to the infinitive group: -ar, -er, -ir. You drop the infinitive ending, then add the imperfect ending.

-Ar Verbs Use -Aba Endings

Take hablar → habl- + endings:

• yo hablaba
• tú hablabas
• él/ella/usted hablaba
• nosotros/as hablábamos
• vosotros/as hablabais
• ellos/ellas/ustedes hablaban

-Er And -Ir Verbs Share -Ía Endings

Take comer → com- and vivir → viv-:

• yo comía / vivía
• tú comías / vivías
• él/ella/usted comía / vivía
• nosotros/as comíamos / vivíamos
• vosotros/as comíais / vivíais
• ellos/ellas/ustedes comían / vivían

Accents In The Imperfect: Don’t Skip Them

Two accent habits matter most:

• -Ía endings always carry an accent in every person: comía, comías, comíamos, comíais, comían.
• Nosotros/as in -aba also carries an accent: hablábamos. That accent helps your eye separate it from other forms.

If you want to cross-check full conjugation models from an official reference, the RAE modelos de conjugación verbal list standard patterns for regular and irregular verbs.

Table 1 (placed after ~40% of content)

Pattern Or Verb	One Clear Example	What To Watch
-Ar Regular (-aba)	hablar → yo hablaba	Nosotros: hablábamos (accent on -ba-)
-Er Regular (-ía)	comer → tú comías	-ía endings always take an accent
-Ir Regular (-ía)	vivir → ellos vivían	-er and -ir share the same endings
Irregular: Ser	yo era	Looks like no ending pattern; memorize full set
Irregular: Ir	nosotros íbamos	Accent on íbamos; forms resemble a “going” pattern
Irregular: Ver	yo veía	Accent stays: veía, veíamos, veíais
Imperfect + Time Setting	Eran las ocho	Use for background time, age, weather, states
Imperfect Progressive	estaba leyendo	Imperfect of estar + gerund for “was doing”

Irregular Verb In The Imperfect Tense Spanish: Ser, Ir, Ver Made Simple

This is the full “irregular” list for the imperfect: ser, ir, ver. That’s it. No stem-changes, no spelling shifts, no surprise clusters. Just three sets of forms to learn and use.

Ser In The Imperfect

Ser often marks what something was like, what someone was like, and what something was. Here are the forms:

• yo era
• tú eras
• él/ella/usted era
• nosotros/as éramos
• vosotros/as erais
• ellos/ellas/ustedes eran

Notice how the stress feels steady when you say it aloud: era, eras, era… It’s one of those sets that sticks once you use it in a few sentences.

Ir In The Imperfect

Ir is the “used to go / would go” verb. It’s also the backbone of travel and routine stories in the past.

• yo iba
• tú ibas
• él/ella/usted iba
• nosotros/as íbamos
• vosotros/as ibais
• ellos/ellas/ustedes iban

One detail that saves mistakes: the only accent in this set is íbamos. It’s easy to drop when typing fast, so train your eye to spot it.

Ver In The Imperfect

Ver is “to see,” and its imperfect forms keep the -ía accent pattern:

• yo veía
• tú veías
• él/ella/usted veía
• nosotros/as veíamos
• vosotros/as veíais
• ellos/ellas/ustedes veían

For official conjugation tables and model paradigms, you can also use the DPD “modelos de conjugación verbal” appendix, which gathers model charts for regular and irregular verbs.

How To Pick Imperfect Vs Preterite Without Overthinking

Most tense mistakes don’t come from endings. They come from choosing the wrong past tense. A clean way to decide is to ask what your sentence is doing.

Choose Imperfect When You’re Painting The Scene

Scene-setting language points to imperfect: time, weather, age, mood, and the “what was going on” layer.

• Esa noche hacía calor y yo tenía sueño.
• Mis amigos estaban en casa y veían una película.

Choose Preterite When You’re Marking A Completed Event

The preterite pushes the story forward with completed actions. If it feels like “then this happened,” you’re likely in preterite territory.

• De repente, sonó el teléfono.
• Yo abrí la puerta y salí.

Use Both Together In One Story

This pairing is common: imperfect for the background, preterite for the event that interrupts or lands as a finished action.

• Leía cuando llegaste.
• Íbamos al centro y de pronto empezó a llover.

If you want short practice that targets imperfect forms (including the irregular trio), the Instituto Cervantes offers structured activities like AVE A2: “El pretérito imperfecto de indicativo”.

Table 2 (placed after ~60% of content)

Common Slip	Quick Fix	Mini Example
Mixing -aba and -ía	Check the infinitive: -ar → -aba; -er/-ir → -ía	hablaba / comía
Dropping accents in -ía forms	Train the pattern: every -ía ending gets an accent	veíamos, comíais
Forgetting íbamos	One accent in ir: íbamos	Cuando éramos niños, íbamos…
Using preterite for descriptions	Descriptions and settings lean imperfect	Era tarde; hacía frío
Overusing imperfect for finished actions	Use preterite for the completed event	Sonó el teléfono
Confusing era and fue	Era = background/state; fue = completed identity/event	Era médico / Fue un error
Confusing iba and fui	Iba = was going/used to go; fui = went (completed)	Iba a casa / Fui a casa

Practice That Builds Real Speed With The Imperfect

You don’t need fancy drills. You need reps that force you to choose endings and tense on purpose. Use these three practice styles and rotate them.

Start With “Before” Routines

Pick five habits you used to have, then write one sentence for each. Keep it plain. Aim for clean endings and one time marker.

• Antes, trabajaba los sábados.
• Cuando era niño, veía dibujos animados.
• De joven, íbamos a la playa cada verano.

Write A Two-Layer Story

Write 6–8 lines. Use imperfect for the scene. Drop in 2–3 preterite actions as “events.” This trains the decision that most learners want.

• Era de noche y la calle estaba vacía.
• Yo caminaba despacio y veía las luces de las tiendas.
• De pronto, alguien gritó mi nombre.
• Me giré y vi a un amigo.

Drill The Three Irregular Sets In One Minute

Set a timer for 60 seconds. Write the full conjugation of ser, ir, and ver from memory. Then check what you wrote. Repeat daily for a week. After that, twice a week is plenty.

Small Details That Make Your Spanish Sound Natural

Once the endings feel automatic, your next wins come from phrase choices that pair nicely with the imperfect.

Time Markers That Pair Well With Imperfect

These time cues often set up routines or background:

• Siempre, a menudo, cada día
• De niño, cuando era joven
• Mientras + imperfect (background action)

“Mientras” Works Like A Signal Light

Mientras often pulls you toward imperfect because it frames an action in progress.

• Mientras estudiaba, mi hermano escuchaba música.
• Mientras íbamos al trabajo, hablábamos de planes.

Ser, Ir, Ver In Natural Sentences

To make the irregular forms stick, place them in sentences you might say.

• Mi abuelo era mecánico y siempre contaba historias.
• Nosotros íbamos caminando, sin prisa.
• Yo veía a mis amigos casi todos los días.

One Last Check Before You Hit Publish Or Submit Homework

When you write in the imperfect, run this quick mental check:

• Is this describing a scene, a state, a routine, or something in progress? If yes, imperfect fits.
• Is this marking a completed past event that moves the story? If yes, the preterite may fit better.
• If it’s ser, ir, or ver, am I using the memorized imperfect forms?
• Did I keep the accents in -ía endings and in íbamos and éramos?

Once those checks become habit, “irregular” stops feeling like a warning label and starts feeling like a tiny list you’ve already mastered.