The Q3 2026 Tax Calendar Every Freelancer Should Pin to the Wall

The third quarter is the one that gets people. Q1 arrives after the January reset, when everyone is organised. Q2 lands in July, annoying but survivable. Q3 covers July, August and September — the three months when half the invoices arrive while you're out of the office, your clients are out of theirs, and nobody is filing anything into a folder.

Then October 1st arrives and you have twenty days to reconstruct a quarter you barely remember.

Here are the dates that matter, what each form is for, what it actually costs to be late, and a working plan to arrive at the deadline with the paperwork already done.

The dates for Q3 2026

The quarter covers 1 July to 30 September 2026. The filing window opens on 1 October.

1–20 October 2026 — the main window for quarterly self-assessments: forms 303, 130 or 131, 111, 115 and 123. 20 October falls on a Tuesday in 2026, so there is no weekend extension to rescue you.
15 October 2026 — the real cut-off if you pay by direct debit. The tax agency closes direct-debit submissions five days before the general deadline, so a filing you intend to have charged automatically must be in by the 15th, not the 20th.
20 October 2026 — also form 349 (intra-EU transactions) and, for companies, form 202 (second corporate income tax instalment).
30 October 2026 — monthly VAT filers (form 303 for September, plus 322 and 353 for entity groups).
5 November 2026 — form 102, the second instalment of your 2025 personal income tax return, if you chose to split the payment.
30 November 2026 — form 232, related-party transactions and operations with tax havens.

If you only remember two numbers from this article, make them 15 and 20.

What each form actually covers

Form 303 — quarterly VAT

Output VAT you charged minus input VAT you paid, for July to September. This is the one that rewards good paperwork and punishes bad paperwork, because every supplier invoice you can't find is deductible VAT you simply hand over. A €400 hosting invoice buried in a WhatsApp thread is around €84 you don't recover.

We wrote a full pre-filing review for the previous quarter, and the same checks apply here: the Modelo 303 checklist to run before you file.

Form 130 (or 131) — income tax instalment

A payment on account of your annual income tax. Form 130 if you're on direct estimation, 131 if you're on the módulos regime. Note that 130 is cumulative across the year — it takes January-to-September income and deducts what you already paid in Q1 and Q2. That means an error in an earlier quarter follows you into this one.

Form 111 — withholdings on employees and professionals

If you have staff, or if you received invoices from other freelancers with IRPF withholding on them, you've been holding that money on the tax agency's behalf since July. October is when you hand it over. This one is worth double-checking: the amounts come from other people's invoices, not yours, so they're the easiest to miss.

Form 115 — withholdings on rent

If you rent an office, a warehouse or a commercial premises, you're withholding tax on the rent and paying it here.

Form 123 and 349

Form 123 covers withholdings on investment income, such as interest on a loan you took from a partner. Form 349 reports intra-EU purchases and sales — relevant if you buy software, ads or services from other EU countries, which most freelancers now do without thinking about it.

Why 15 October is the date that actually bites

Direct debit is the sensible way to pay: you file, the tax agency charges your account on the 20th, and you keep the cash a few extra days. But you have to file by the 15th for that to work.

Miss it, and you're not late yet — you just lose the easy payment route. You now have to pay through your bank with an NRC reference code before you can submit. That's a live bank transaction on a working day, with enough money sitting in the account at that moment. It's the difference between a five-minute task and an afternoon of stress, and it's the single most common way a well-prepared quarter still turns messy.

Treat the 15th as your deadline. The 20th is your buffer, not your plan.

What being late actually costs

The surcharge system was rewritten by Law 11/2021 and is now much gentler than the old 5%–10%–15%–20% steps. Under article 27 of the General Tax Law, if you file late but before the tax agency contacts you:

The surcharge is 1%, plus another 1% for each full month of delay.
After 12 months, it jumps to a flat 15%, and late-payment interest starts accruing from that twelve-month mark onwards.
The surcharge is reduced by 25% if you pay both the tax due and the surcharge within the deadlines set when it's notified to you.
Filing voluntarily excludes the penalties that could otherwise apply.

So one month late on a €2,000 VAT bill is roughly €40, dropping to about €30 with the reduction. Not catastrophic. But the important word in all of this is *voluntarily*: the favourable regime only applies if you go to them before they come to you. Once you get a formal request, you're in a different and much more expensive conversation.

The three-week plan

The deadline isn't the problem. The problem is that the work you need to do — collecting three months of documents — can't be done in the last week. Here's the version that works.

Weeks of 21 and 28 September: hunt, don't process. Don't try to book anything yet. Just find every supplier invoice from July, August and September. Email, WhatsApp, the photo of a petrol receipt on your phone, the PDF a supplier sent to a colleague. Get them into one folder. This is the step that decides how much VAT you actually recover — most of what people lose isn't lost in the accounting, it's lost before it ever reaches the accounting. We went through that in detail in the deductible input VAT you lose every quarter.

Week of 5 October: process and reconcile. Turn the folder into rows: date, supplier, tax ID, base, VAT rate, VAT amount, total. Then reconcile against your bank statement. Anything charged to the account without a matching invoice is a document still missing. Anything with an invoice but no charge might be unpaid — or a duplicate you're about to book twice, which is more common than it sounds.

By 13 October: draft the numbers. Calculate 303 and 130 with what you have. If the result looks wrong, you still have two days to investigate rather than two hours.

14–15 October: file with direct debit. Done, five days before everyone else starts panicking.

If your team is thin during the summer and this plan looks optimistic, the fix isn't more discipline in October — it's capturing documents as they arrive in August. That's the argument we made in closing the quarter in August with half your team on vacation.

Two 2026 changes worth knowing about

Rectifying self-assessments are now the normal route for VAT errors. If you spot a mistake in a 303 you've already filed, you no longer send a separate correction request in most cases — you file a rectifying self-assessment. This mechanism has applied to quarterly VAT periods from Q3 2024 onwards. There are exclusions, notably VAT incorrectly charged to another taxpayer, which still goes through the old rectification request. It means an error found on 25 October is a manageable problem, not a disaster.

Verifactu is not a 2026 deadline any more. This one has moved twice and a lot of published calendars are still wrong. Royal Decree-Law 15/2025, of 2 December, postponed the certified-invoicing-software requirement by a further year. Corporate income tax payers now have until 1 January 2027, and freelancers on personal income tax, non-residents with a permanent establishment and income-attribution entities until 1 July 2027. If someone told you your invoicing software had to be compliant by July 2026, that's no longer the case — but the extension is a year, not a reprieve.

The honest summary

Q3 doesn't demand more tax than the other quarters. It demands better archaeology, because the documents are scattered across three of the least organised months of the year.

The fix is boring and it works: get the documents into one place before October starts, reconcile against the bank, file by the 15th with direct debit, and keep the 20th as slack you never use.

If the hard part for you is turning a pile of PDFs and photos into rows you can actually add up, that's exactly the step you can automate — try it free, no signup: send an invoice and get the data back structured in seconds.