Information on Regional Tax Authorities

Bizkaia

Tax information telephone number: 946 125 500

Website of the Provincial Council of Bizkaia: www.bizkaia.eus

The Official Gazette of Bizkaia of June 15, 2026, has published the Regional Order 298/2026, of June 5, of the Provincial Deputy for Finance and Treasury, which regulates the procedure for the presentation of self-assessments for Corporation Tax and Non-Resident Income Tax, corresponding to permanent establishments and entities under the income attribution regime established abroad with a presence in the Historical Territory of Bizkaia, for tax periods beginning on or after January 1, 2025.

Following the completion of the system implementation process Batuz On December 31, 2025, the Department of the Treasury and Finance will make draft tax returns available to taxpayers of Corporate Income Tax and Non-Resident Income Tax, corresponding to permanent establishments and entities under the income attribution regime established abroad with a presence in the Historical Territory of Bizkaia, through the web application enabled in the electronic headquarters of the Provincial Council of Bizkaia.

In the 2024 Companies Campaign, the Department of Finance and Treasury developed a application for the preparation and submission of the aforementioned self-assessments for those taxpayers subject to the Biscayan tax regulations, on the electronic headquarters of the Provincial Council of Bizkaia.

The Provincial Law 2/2025, of April 9, which approves measures for the fiscal review of the tax system of the Historical Territory of Bizkaia, has introduced important modifications to the Corporate Income Tax in various areas.

Preparation and submission of self-assessments

1. Taxpayers subject to the regional regulations of Bizkaia

   Prior to the submission of the corresponding self-assessment, the Provincial Council of Bizkaia, upon request of the taxpayers, will make draft self-assessments available to them.

   To prepare the self-assessments of those entities subject to the Corporate Income Tax regulations of the Historical Territory of Bizkaia, both under the individual taxation regime and the tax consolidation regime, as well as for their subsequent submission, the declarant or, where applicable, the representative person or entity, must use the web applications enabled for this purpose on the electronic headquarters of the Provincial Council of Bizkaia.

2. Taxpayers subject to other regulations

   To prepare the self-assessments of those entities subject to the Corporate Tax regulations of the Historical Territory of Araba/Álava, Gipuzkoa or the common territory, which pay taxes in the Historical Territory of Bizkaia in proportion to the volume of operations carried out in this Territory, the declarant or, where appropriate, the representative person or entity, must use the computer means developed by the Regional Treasury of Araba/Álava, the Regional Treasury of Gipuzkoa or the State Agency of the Tax Administration, respectively, and, subsequently, use the appropriate file conversion program from among those available on the website of the Provincial Council of Bizkaia, to obtain the file that must be transmitted through its electronic headquarters to complete the presentation.

Filing period

The electronic filing of self-assessments, regardless of whether they are positive, negative or result in a refund, as well as the payment, where relevant, will take place within twenty-five calendar days following the six months after the conclusion of the tax period.

When at the beginning of the indicated period the head of the Department of Treasury and Finance has not determined the manner of presenting the self-assessment for that tax period, in which case the self-assessment shall be presented within twenty-five calendar days following the date of entry into force of the provision that determines said manner of presentation.

Payment methods

For tax years beginning on or after January 1, 2025, if the result of the self-assessment is to returnDirect debit will be mandatory, irrevocable, and must meet the following conditions:

1. The Regional Treasury of Biscay must be informed of the ownership of the IBAN code.

2. The holder of the IBAN Code must be the Declarant of the tax return being submitted.

With self-assessments that result in a payment due, the taxpayer can choose to pay via direct debit or via a paying-in slip.

For self-assessments that result in a payment due that are paid by direct debit, as well as the two previous conditions, the selected financial institution must be an entity that collaborates with the Regional Treasury of Biscay in tax collection.

Notwithstanding the foregoing, payment may be made through other means available on the Bizkaia Provincial Council's electronic site.