If you’ve ever tried to pin down when tax season starts and ends, you know it’s not a one-size-fits-all answer — especially when you’re comparing two different countries. In 2026, Ireland’s tax year runs from January 1 to December 31, with a filing deadline of October 31, while the U.S. IRS opens e-filing on January 26 and sets April 15 as the main due date.
Irish tax year: 1 January to 31 December ·
Standard filing deadline (ROS): 31 October 2026 ·
Extended e-filing deadline (ROS): 18 November 2026 ·
Paper return deadline: 31 October 2026 ·
US IRS filing season start: 26 January 2026 ·
US tax extension deadline: 15 October 2026
Quick snapshot
- Irish tax year: 1 January to 31 December (Raisin (financial services))
- US filing deadline: 15 April 2026 (Internal Revenue Service (U.S. tax authority))
- Irish Pay and File deadline: 31 October 2026 (Raisin)
- US extended deadline: 15 October 2026 (Consumer Financial Protection Bureau (U.S. federal agency))
- Whether the IRS could shift the start date due to legislation changes (H&R Block (tax preparer) has estimated Jan 26, but not officially confirmed)
- Exact impact of possible Revenue strike actions on ROS availability (Revenue (Irish tax authority) calendar may be affected)
- Irish ROS extended e-filing window closes 18 Nov 2026 (Raisin)
- US extension deadline 15 Oct 2026 (CFPB)
Six key dates, one contrast: Ireland gives you until the last day of October to file, while the U.S. requires most people to finish by mid-April but offers a six-month extension.
The table below lays out the core numbers side by side.
| Item | Value |
|---|---|
| Irish tax year | 1 January to 31 December |
| 2025 return deadline (paper) | 31 October 2026 |
| 2025 return deadline (ROS e-file) | 18 November 2026 |
| US filing start date | 26 January 2026 |
| US extension deadline | 15 October 2026 |
| Irish 40% tax threshold (single) | €42,000 |
What date are tax returns due in Ireland?
Standard deadline for paper and ROS filers
For the 2025 tax year, the Irish Pay and File deadline falls on 31 October 2026 — that applies whether you file on paper or through the Revenue Online Service (ROS). According to Raisin (financial services platform focused on Ireland), the deadline is midnight on that date for all self-assessment taxpayers. If you miss it, late filing surcharges kick in immediately.
Extended deadline for e-filing through ROS
Revenue Ireland does offer a small grace window for electronic filers: you can submit your return via ROS up to 18 November 2026. As noted in Revenue (Irish tax authority) calendar, this extension is only for e-filed returns — paper filers still must meet the October 31 cutoff. The catch: any tax you owe must still be paid by 31 October to avoid interest charges.
“If you need to do a tax return, the deadline for submitting it for the Irish tax year … is midnight on 31 October 2026.”
— Raisin, financial services publication
Irish self-assessment filers get a longer runway than Americans — nearly ten months after the tax year ends — but the penalty for missing the hard deadline is steep: a 5% surcharge on the tax due, plus daily interest.
The implication: If you file your Irish return by 18 November via ROS, you avoid the late-filing surcharge, but you still need to pay any balance by 31 October to stop interest running.
What is the start of tax season?
Irish tax year start (1 January)
Ireland operates on a calendar tax year: 1 January to 31 December. That means the 2025 return covers income earned from 1 January 2025 through 31 December 2025. Raisin confirms this period is standard for all Irish self-assessment taxpayers.
US IRS filing season start (26 January 2026)
Across the Atlantic, the IRS is expected to begin accepting e-filed returns on 26 January 2026. H&R Block (leading U.S. tax preparation service) reports this date as the opening of the 2026 filing season, though the IRS has not yet issued an official press release. Many taxpayers start gathering documents in late December.
“The IRS site states that if day 15 falls on a Saturday, Sunday, or legal holiday, the due date is delayed until the next business day.”
The gap between the U.S. start (late January) and the Irish start (1 January) is a reminder that “tax season” means different things in each country. For U.S. filers, the season is compressed into about 2.5 months; Irish filers have until late October to complete their return.
The pattern: Ireland gives you a full year after the tax year ends to file; the U.S. gives you roughly 3.5 months. That difference shapes how accountants and self-employed people plan their workflows on both sides.
When is the end of the tax year 2025/26?
Irish tax year end (31 December 2026)
The Irish tax year ends on 31 December 2026. For the return you file in 2026 (covering 2025 income), the relevant end date was 31 December 2025. As Raisin notes, this calendar-year system is straightforward: your filing is always due on 31 October of the following year.
UK tax year dates (5 April window)
Note: The UK tax year ends on 5 April, not 31 December. This can confuse expats or business owners who operate in both Ireland and the UK. For Ireland, ignore the 5 April date — the self-assessment system is entirely calendar-based.
The CFPB confirms that for U.S. taxpayers, the 2025 return covers income from January 1 to December 31, 2025, and is due April 15, 2026. The end of the tax year is the same calendar date in both Ireland and the U.S., but the filing windows diverge.
What this means: If you’re comparing Irish and U.S. deadlines, remember that the tax year end is identical, but the filing clock starts ticking much earlier in the U.S.
Can I extend my tax filing past October 15?
Irish extension policy (ROS only)
In Ireland, the only automatic extension is the ROS e-filing window to 18 November 2026. As Revenue (Irish tax authority) calendar shows, no further extension is available — paper filers get no grace period. Payment must still be made by 31 October to avoid interest.
US extension options (Form 4868)
U.S. taxpayers can get an automatic 6-month extension by filing Form 4868 with the Internal Revenue Service by the original due date. This pushes the filing deadline to 15 October 2026. However, the CFPB warns: “if a taxpayer expects to owe taxes, the amount due should be estimated and paid with the extension form.” The payment deadline remains 15 April 2026.
“You can request an automatic 6-month extension of time to file.”
— Internal Revenue Service
U.S. expats living abroad on April 15 qualify for an automatic filing extension to June 15, 2026, but the payment deadline remains April 15. Failure to pay on time triggers penalties even if the return isn’t due until later.
The trade-off: Ireland’s extension is short (18 days) and only for e-filing; the U.S. gives you six extra months to file but demands payment upfront. Expats get a slightly longer filing window but the same payment cliff.
How much can I earn before I pay 40% tax in Ireland?
2025 income tax bands and rates
For the 2025 tax year (filed in 2026), the 40% higher rate in Ireland applies to income above €42,000 for a single person. Raisin references this threshold as part of the self-assessment context. Married couples benefit from higher bands — up to €51,000 for a one-earner couple and €84,000 for two earners under certain conditions.
US tax bracket comparison
In the U.S., the 2025 tax brackets are very different. The 22% bracket for a single filer starts at about $47,150, and the 35% rate kicks in at $243,725. Direct comparison is tricky because of deductions and credits, but the key point: Ireland’s 40% threshold is relatively low by U.S. standards. Anyone earning over €42,000 in Ireland should expect to pay the top marginal rate on income above that line.
The implication: If you’re a dual filer or comparing tax burdens, Ireland’s 40% rate kicks in at a much lower income level than the U.S. top tax rates, making tax planning especially important for higher earners.
Timeline: 2026 Tax Season at a Glance
- — Start of Irish tax year 2026
- — US IRS filing season begins (H&R Block)
- — Deadline for US partnership (Form 1065) and S-corporation returns (Bloomberg Tax (specialist tax publisher))
- — US federal tax deadline (standard) (IRS)
- — Expats filing deadline (automatic two-month extension) (Online Taxman (tax advisory publication))
- — US extended filing & FBAR final deadline (CFPB)
- — Irish Pay and File deadline (paper & ROS) (Raisin)
- — Extended ROS e-filing deadline
What We Know and What’s Still Uncertain
Confirmed facts
- Irish tax year is 1 January to 31 December (Raisin)
- Deadline for 2025 return is 31 October 2026 (paper and ROS)
- ROS e-filing extended to 18 November 2026
- US filing season starts 26 January 2026 (H&R Block)
What’s unclear
- Whether IRS will shift the start date due to legislation changes
- Exact date for possible Revenue strike actions affecting ROS availability
1040abroad.com, fusiontaxes.com, taxesforexpats.com, greenbacktaxservices.com
Frequently Asked Questions
What happens if I miss the tax return deadline in Ireland?
Late filing triggers a 5% surcharge on the tax due (up to a maximum) and daily interest. If you file after 18 November, the surcharge applies even if you use ROS. Source: Revenue Ireland.
Is it mandatory to file a tax return if I am a PAYE employee in Ireland?
Not usually — if your only income is from PAYE employment and the tax deducted is correct, you don’t need to file. But if you have other income or claim certain reliefs, you may need to register for self-assessment.
How do I claim tax back online in Ireland via Revenue?
Log into myAccount on Revenue.ie, select “Review your tax” and follow the prompts to claim refunds for health expenses, tuition, or flat-rate expenses. Most refunds are processed within 5-10 days.
Can I e-file my US taxes after the April 15 deadline?
Yes, if you file an extension (Form 4868) by April 15, you can e-file until October 15. Without an extension, filing after April 15 may still be accepted but penalties apply. Source: IRS.
Do I need to file a tax return in Ireland if my income is below the threshold?
If your total income is below the standard rate cut-off point (€42,000 for a single person) and you paid the correct PAYE/PRSI, you generally don’t need to file. But if you owe tax on non-PAYE income, you must file.
What are the penalties for late filing of Irish tax returns?
A surcharge of 5% of the tax due (max €12,695) for returns filed after the deadline, plus interest at 0.0219% per day. Deliberate non-compliance can lead to higher penalties.
For an Irish self-assessment filer, the tax season ends in late October with a short e-file extension into November — a generous window but one that demands strict attention to the payment deadline. For a U.S. taxpayer, the season compresses into early spring, with an automatic six-month extension for filing but no relief on payment. The choice between the two systems isn’t about which is “better” — it’s about knowing which deadline applies to your situation, and planning ahead so you don’t face penalties.