Ireland ROS September Week-Two Prep: PAYE, VAT and CT1 Countdown
As of 3 September 2026, Irish SMEs should lock week-two ROS prep before August PAYE on 14 September — bi-monthly VAT on 19 September and CT1/RCT through 23 September follow, with August IOSS still due 30 September.
Revenue’s Calendar of key dates for tax professionals sets September’s Irish SME ROS rhythm: PAYE/PRSI/USC/LPT for August on 14 September (payment extended to 23 September for ROS users who file and pay online), a dense VAT 3 cluster on 19 September including July–August bi-monthly returns, and Corporation Tax plus RCT obligations through the 23rd. As of Thursday 3 September — eleven days to the PAYE return date — protect week-two prep slots before mid-month leave thins coverage.
Treat August IOSS (due 30 September) as a separate month-end track that must not steal the September PAYE and VAT prep slots. Domestic VAT 3 and IOSS never replace each other.
Sequence from this week through late September
3–7 September — finish locking August payroll runs, reconcile July–August sales and purchase ledgers, and keep iXBRL / Form 46G gathering moving for December year-end CT1.
14 September — August PAYE monthly return (and DWT/PSWT where due); ROS payment extension to 23 September only if you file and pay online.
19 September — monthly August VAT 3, bi-monthly July–August VAT 3, four-monthly May–August, and annual cycles ending in August, plus Return of Trading Details where required.
1–23 September — CT1 and corporation tax balance for December 2025 year-ends under mandatory e-filing; RCT monthly return for August on 23 September. Diary 30 September for August IOSS so July’s close-out does not cascade.
Week-two prep checklist
Confirm July IOSS cleared on 31 August — chase any stranded payments before week-two payroll close.
Lock August payroll runs and employee changes before mid-September leave thins coverage — the 14 September return date is eleven days away.
Reconcile July and August sales and purchase ledgers for the bi-monthly VAT pack while July ROS cash journals are still fresh.
Continue iXBRL and Form 46G gathering for December year-end CT1 so validation is not a 22 September surprise, and confirm ROS digital certificates for the late-September cash days.
How FinnAccountings helps through September ROS
Organised books make multi-deadline ROS months easier to review. FinnAccountings helps Ireland and UK businesses prepare bookkeeping, payroll, and tax packs with Chartered Accountant insight before you or your Chartered Accountant (Ireland) or ICAEW/ACCA adviser files. Start a free trial for review-ready drafts — we prepare records; we do not file ROS returns or make Revenue payments on your behalf.
Related reading
Monday’s week-one after-IOSS briefing still maps the full ROS sequence.
August PAYE has eleven days to the 14 September return as of the 3 September midday brief.
December year-end CT1 has twenty days to 23 September as of the 3 September midday brief.
Bi-monthly July–August VAT has sixteen days to 19 September as of the 3 September midday brief.
Sources & references
This article draws on official guidance and publications from the sources below.
- 1.Calendar of key dates for tax professionals
Revenue (Irish Tax and Customs) · Accessed 2026-09-03
- 2.Corporation Tax (CT) payment and filing
Revenue (Irish Tax and Customs) · Accessed 2026-09-03
- 3.When VAT becomes payable
Revenue (Irish Tax and Customs) · Accessed 2026-09-03
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FinnAccountings helps with bookkeeping, tax, and VAT prep for Ireland and the UK — with Chartered Accountant insight on AI drafts. Educational articles are not filing advice.
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