This is an irregular verb. It follows the conjugation pattern of the verb parecer.
PresentPresente
Abastecen a toda la región con agua potable.
They supply the entire region with clean water.
PreteritePretérito indefinido
Los camiones abastecieron la ciudad durante la emergencia.
The trucks supplied the city during the emergency.
Present SubjunctivePresente de subjuntivo
Es importante que abastezcan comida con regularidad.
It's important that they supply food regularly.
Imperfect SubjunctiveImperfecto de subjuntivo
Era necesario que un camión abasteciera la tienda cada semana.
It was necessary for a truck to supply the store every week.