August also has dates marked in red on the fiscal calendar. The Tax Agency maintains this Thursday, August 20, 2026, several deadlines that affect, among others, large companies and taxpayers subject to certain special taxes. The next important deadline will arrive on August 31, when the period for submitting the monthly VAT for July and other declarations will end.
The official calendar of the Tax Agency establishes three deadlines during August: the 12th, 20th, and 31st. The first has already passed, while this Thursday concludes the deadline for a broad group of tax obligations.
This does not mean that all self-employed individuals, companies, or individuals have to submit these forms. Each obligation affects specific taxpayers depending on their activity, size, tax regime, and frequency of submission.
What forms are due today, August 20
One of the main blocks corresponds to withholdings and advance payments of Income and Corporate Tax for July for large companies. The deadline ends this Thursday for the forms 111, 115, 117, 123, 124, 126, 128, 216, and 230.
Among them are the withholdings related to income from work and economic activities, rentals of urban properties, certain income from movable capital, and income obtained by non-residents without a permanent establishment.
In terms of VAT, on August 20, the form 308 also expires for certain taxable persons under the simplified regime who carry out passenger or freight transport activities by road and request the corresponding refund for the acquisition of certain means of transport.
Special taxes with a deadline this Thursday
The Treasury calendar also concentrates on this August 20 different obligations related to Manufacturing Special Taxes. For large companies, the forms 561, 562, and 563 corresponding to May appear, while for the rest of the taxpayers obligated to these forms, the deadline corresponds to the second quarter of 2026.
For July, the Tax Agency includes the forms 548, 566, and 581, in addition to the self-assessment form 573 and the refund request A24. The form 510 for the declaration of operations of registered recipients and tax representatives is also listed.
These obligations are joined by the model 560 of the Special Tax on Electricity, corresponding to July for large companies; the model 592 of the special tax on non-reusable plastic packaging and the model 604 of the Tax on Financial Transactions.
The monthly VAT for July is due on August 31
The last major tax deadline of the month will arrive on Monday, August 31. That day marks the end of the deadline to submit the model 303 for self-assessment of VAT corresponding to July 2026 for taxpayers who are required to settle it monthly.
The same date applies to the models 322 and 353, corresponding to the special regime of the group of entities. The model 369 of the single window for the import regime and the model 380 for operations assimilated to imports is also due.
This does not imply that self-employed individuals who submit VAT every three months have to submit a new declaration in August. The due date for model 303 on the 31st corresponds to the monthly period of July, not to the ordinary quarterly submission.
Two informative declarations also end on August 31
The calendar of the Tax Agency also reserves the last day of the month for two informative declarations corresponding to July. One of them is model 170, related to certain operations carried out using cards and payments associated with mobile phone numbers.
The second is the model 196, related to accounts in financial institutions and with the summary of certain withholdings and income on account of returns from movable capital and income obtained as consideration for those accounts.
In this way, after the deadlines of this Thursday the 20th, August 31 will be the last relevant tax date of the month within the general calendar published by the Treasury.
Table: tax models due on August 20 and 31, 2026
| Deadline | Obligation | Models |
|---|---|---|
| August 20 | Withholdings and income on account for July for large companies | 111, 115, 117, 123, 124, 126, 128, 216 and 230 |
| August 20 | Certain VAT refund | 308 |
| August 20 | Special taxes, electricity, plastic and financial transactions | 510, 548, 560, 561, 562, 563, 566, 573, 581, 592, 604 and A24 |
| August 31 | Monthly VAT for July | 303, 322, 353, 369 and 380 |
| August 31 | Monthly informative declarations | 170 and 196 |
August does not paralyze the deadlines of the Treasury
That August is a month traditionally associated with vacations does not generally suspend tax obligations. Taxpayers included in any of these cases must respect the dates established in the tax calendar.
In addition, the submission date and the bank direct debit date do not always coincide. For certain self-assessments with direct debit payment, the deadline to order the direct debit ends before the general submission deadline.
Therefore, before carrying out the procedure, it is advisable to check the specific form, the corresponding period, and the payment method. The appearance of a declaration in the August calendar does not by itself mean that all taxpayers are required to submit it.