• IRS - personal income tax
- Delivery of amounts withheld in the previous month for Tax on Income of Individuals (IRS).
• IRC - Corporate income tax
- Delivery of amounts withheld in the previous month, for Corporate Income Tax
• Stamp Duty
- Delivery of amounts withheld in the previous month, for Stamp Duty. 
• VAT - Value added tax
- Small Retailers - Delivery Model P2 statement or Model P2 statement or Model 1074 form, depending on whether or not tax has to be paid regarding the 1st quarter of 2013.
- Recapitulative Statement - Delivery of the Recapitulative Statement Delivery by taxpayers in the normal monthly regime who have made intra-Community supply of goods and/or services to other Member States, in the previous month, and for taxpayers under the normal quarterly regime, when the total intra-Community transmission of goods to include in the declaration has, in the current quarter, exceeded the amount of J 50.000.

Until the 25th

• VAT - Value added tax
Communication via electronic transmission of data elements on the invoices issued the previous month by individual or corporate taxpayers having their registered headquarters, offices or tax residence in Portuguese territory and execute operations subject to VAT in this territory.

Until the 31st

• IRC - Corporate tax
- Submission of periodic statement, Model 22, via electronic transmission of data by entities subject to IRC whose tax period coincides with the calendar year, and payment of the corresponding tax.
• IRS - Tax on personal income 
- Submission of statement Model 3, via electronic data transmission, by taxpayers with incomes of Category A (dependent work), B (business and professional), E (capitals), F (real estate), G (capital gains) and H (pensions), together with Appendix J, if income was earned abroad, and Annex H if there are ax benefits, deductions to tax application, additions or exemptions subject to aggregation.
- Submission of Model 18 Statement, via electronic transmission of data, by the Entities issuing meal vouchers.
• VAT - Value added tax
- Submission of VAT refund request by taxpayers of tax paid, on the same calendar year, in another Member State or third country, when the amount to be reimbursed exceeds J 400 and in respect of a period not less than three consecutive months.
• IUC - Single Road Tax
- Settlement and payment of the Single Road Tax - IUC, on vehicles whose register aniversary occurs in May.

Source: "Vida Económica"