The AEAT tax calendar 2026: every deadline for law firms

A law firm lives by its clients’ deadlines: the appeal that expires, the defence brief that’s due, the official request that must be answered in time. And yet the firm’s own deadlines as a business — the tax ones — are often managed worse than those of any case file. The firm trusts the gestoría to remember, discovers the VAT return on the 18th, and ends up paying a surcharge because the direct debit window had already closed.

We’re halfway through 2026, so this article serves two purposes: as a complete map of the year, and as a reminder of what still lies ahead — which is plenty. July, October and January 2027 concentrate most of a firm’s remaining tax work.

One warning before anything else, because with deadlines precision is everything: the dates below are the general rules. When the last day falls on a Saturday, Sunday or public holiday, the deadline moves to the next working day, and some forms have particularities depending on the taxpayer’s size and regime. Before treating any date as final, confirm it against the taxpayer’s calendar the AEAT publishes on its electronic office (sede.agenciatributaria.gob.es).

The quarterly rhythm: four forms, four appointments a year

The backbone of a firm’s tax calendar is the quarterly filings. As a general rule they’re filed between the 1st and the 20th of April, July and October — for the first, second and third quarters — and between 1 and 30 January for the fourth.

The usual forms in a law firm are these:

• Modelo 303 (VAT). Filed by practically every firm, whether a company or a self-employed lawyer. It declares the VAT charged on your invoices and the VAT paid on your expenses.
• Modelo 130 (IRPF instalment). Only for self-employed lawyers under estimación directa. It’s the quarterly advance payment of personal income tax on the activity’s profit. Companies don’t file it; their equivalent is the corporate tax instalment.
• Modelo 111 (withholdings on employees and professionals). If the firm has staff on payroll, or pays invoices from other professionals subject to withholding — a collaborating lawyer, a procurador, an expert witness — those withholdings are paid in quarterly through this form.
• Modelo 115 (withholdings on rent). If the firm occupies a rented office whose landlord invoices with withholding, that withholding is paid in quarterly through the 115.

Four forms, and not all of them apply to everyone. The exact combination depends on how your firm is set up, and that deserves its own section.

Which forms apply, depending on how your firm is built

A self-employed lawyer, no staff, working from home or from their own premises: modelo 303 every quarter and modelo 130 every quarter. The simplest case.

Self-employed with a rented office: the above, plus the quarterly modelo 115 for the rent withholding, and its annual summary (modelo 180) in January.

Self-employed with an employee — a trainee, a secretary — or paying collaborators with withholding: add the quarterly modelo 111 and its annual summary (modelo 190) in January.

A company (SL) with no employees beyond the partner: quarterly modelo 303, the modelo 200 corporate tax return in July, corporate tax instalments (modelo 202) where applicable, and the 111 to the extent there are salaries or professional withholdings. No modelo 130 — that one is for individuals only.

A company with a team and a rented office: the full picture — 303, 111 and 115 quarterly; 390, 190 and 180 in January; 200 in July; and the 347 in February where it applies.

And one cross-cutting note: if your firm provides services to business clients in other EU countries — common in firms with an international client base — you probably also file modelo 349 for intra-Community transactions, generally on schedules that track the quarterly ones. Confirm it with your adviser, because the frequency can vary.

January: the month of annual summaries

January is the densest month in the calendar. On top of the fourth-quarter returns for 2026 — filed, as a general rule, between 1 and 30 January 2027 — the annual summaries are due: modelo 390 (the annual VAT summary), modelo 190 (the summary of withholdings on employees and professionals, if you filed the 111) and modelo 180 (the summary of rent withholdings, if you filed the 115).

The summaries carry no payment: they’re informative. But they require everything declared during the year to reconcile, and that’s where a firm with disorderly invoicing loses whole days in the middle of January. The best preparation for January happens in November.

In February comes modelo 347, the declaration of transactions with third parties: you report the clients and suppliers with whom you exceeded the annual threshold (as a general rule, 3,005.06 euros). It’s informative, but the AEAT cross-checks it against what your clients and suppliers declare, so discrepancies end in an official query.

The annual appointments: Renta, corporate tax and the 720

Three more deadlines complete the year:

• Modelo 720 (declaration of assets and rights held abroad): filed between January and March. It affects the lawyer — or the company — with accounts, securities or property outside Spain above the thresholds. In a firm with an international practice, that’s not an exotic scenario.
• The Renta campaign: roughly April to 30 June. For the self-employed lawyer it’s the final settlement of the previous year’s income tax, where the modelo 130 instalments are deducted. For 2026 it’s already behind us; the next one comes in spring 2027.
• Corporate tax, modelo 200: for companies whose financial year matches the calendar year, from 1 to 25 July. If your firm is an SL, this July brings — on top of the second quarter — the corporate tax return for 2025.

What’s left of 2026, seen from July

At this point in the year, a firm’s outstanding map comes down to this. In July: the second-quarter filings (1st to the 20th, as a general rule) and, for companies, the modelo 200 until the 25th. In October: the third-quarter filings, 1st to the 20th. And in January 2027: the fourth quarter and the annual summaries, followed by the 347 in February.

One detail that catches someone out every quarter: if you pay by direct debit — which is the convenient and sensible option — the filing window with direct debit closes a few days before the general deadline. The 20th is not the 20th if you want the bank to pay for you. Put the direct-debit date in your calendar, not the theoretical deadline, and check the exact cut-off for each form in the AEAT calendar.

VeriFactu is already here, and it touches this calendar

Since 2026, the invoicing systems of most firms are subject to the VeriFactu regulation (Royal Decree 1007/2023, with deadlines as amended by Royal Decree 254/2025): from 1 January for corporate income tax payers and from 1 July for everyone else, including self-employed lawyers.

For the tax calendar this has a practical reading: invoicing records are now generated in a controlled, tamper-proof format, which means the data feeding the 303, the 130 or the 390 comes out of a system that is orderly by design. If you’re still not sure where your firm stands, the detail is in our VeriFactu guide for law firms.

An owner for the calendar, not a hope

The most common management mistake isn’t ignoring the deadlines: it’s assigning them to no one. “The gestoría handles that” is a reasonable sentence until the quarter when the gestoría asks for the figures on the 15th and nobody has them ready. The gestoría files; the data, the judgement and the ultimate responsibility remain the firm’s.

The fix is the same one you apply to case files: treat tax deadlines like procedural deadlines. One person at the firm owns the tax calendar; every form is a recurring task with a date, an owner and enough lead time — including the direct-debit cut-off; and the paperwork gets prepared days ahead, not the night before.

How Mandato helps

In Mandato, tax deadlines live where the firm’s other deadlines already live: in the shared calendar, as recurring tasks with an owner and reminders, visible to the whole team just like a hearing or a procedural due date. The quarter stops depending on anyone’s memory.

The data side gets lighter too: the firm’s invoicing is recorded and organised at the source, and with the Holded integration that information flows into the accounts — so when the asesoría asks for the quarter’s numbers, they’re ready in minutes rather than afternoons.

The 2026 tax calendar isn’t complicated: it’s repetitive, which is a different thing. And repetitive work is exactly the kind a well-organised firm turns into routine — the same discipline you apply to your clients’ deadlines, applied to your own.