Summer Tax Calendar: The Filings Your Business Can’t Miss in July and August 2026

For many self-employed professionals and small businesses, summer means slowing down. On the Spanish Tax Agency’s calendar, though, July remains one of the busiest months of the year: the close of the second quarter coincides with the annual settlement of several taxes from the previous year. Anyone who assumes “the tax office slows down in summer too” risks coming back from holiday to an entirely avoidable surcharge.

What’s due in July and August

As with every quarterly close, the first twenty calendar days of July bring the VAT return (Form 303) and the withholdings return on employment income and professional services (Form 111), along with Form 115 for anyone renting out business premises. On top of these, the same period includes the annual summaries for the previous tax year: Form 390 (the annual VAT summary, although many self-employed workers under modules or with lower turnover may be exempt) and Form 190 (the annual withholdings summary). Companies also need to keep in mind the Corporate Tax installment payment due for this period, filed on Form 202. Businesses with direct debit set up usually have a slightly earlier deadline than those paying by reference number or filing without direct debit, so it’s best not to leave it until the last moment.

August, by contrast, works more like a transition month: no new quarterly obligations kick in, but that doesn’t make it a blank month in your dealings with the tax authorities. Deadlines for responding to requirements, electronic notifications and any open procedures keep running as normal, with a few specific exceptions worth checking case by case. It’s also when many accounting firms wrap up the second quarter’s paperwork to leave September clear.

What this means for your business

For a self-employed professional or small business, this translates into some very concrete decisions. First, check before heading off on holiday whether your business is required to file Form 390, or whether your tax regime or turnover exempts you that year; filing it when you don’t strictly need to isn’t a problem, but forgetting it when you do creates a formal requirement from the tax office. Second, if you invoice through a company, check with your advisor whether it’s more favorable to calculate the Corporate Tax installment under the general method or the taxable-base method — the cash-flow difference between the two can be significant if your business’s pace has shifted from the previous year. Third, leave direct debits with enough margin: an account without sufficient funds on the charge date causes the same problem as missing the deadline altogether.

July is also a good moment to take a first-half snapshot: reconcile input and output VAT, verify that withholdings applied to professionals match what’s been declared, and confirm that payroll for the period is properly recorded. Catching a discrepancy in July is far cheaper, in both time and penalties, than discovering it at the fourth-quarter settlement or, worse, in a later review by the tax authorities. Surcharges for late filing without a prior request from the tax office are notably lower than those applied once the Administration has already flagged the issue — so the advantage always lies in acting first.

Getting ahead, the best tax strategy

Neither July nor August should bring tax surprises if the business’s finances are kept up to date the rest of the year. The key isn’t memorizing every deadline, but keeping accounting and VAT records continuously current, so that filing any return becomes routine rather than a race against the clock. At Zythos Business, this is exactly what we help self-employed professionals and small businesses with: we review in advance which forms apply at each close, calculate the installment payment using whichever method best fits the business’s actual performance, and make sure no deadline depends on anyone’s memory — so that summer stays a calm period, tax-wise included.