As a general rule, VAT must be self-assessed and the VAT return forms submitted to the local tax office for each quarterly period beginning on the first day of January, April, July and October of every calendar year. Businesses must file their quarterly VAT returns in Spanish form 303.
VAT returns must be submitted and the tax paid within the 20 calendar days of April (for the first quarter), July (for the second quarter), October (for the third quarter) and within the first 30 calendar days of January of the next following year with respect to the last quarter of the preceding year.
However, certain qualifying businesses must account for and pay VAT monthly beginning on the first day of each calendar month. In this case, tax returns must be filed and the tax paid within the first 20 calendar days of the month following each monthly period, all this depending on the size and sales of the company.