Ireland ROS Weekend Close: Monday IOSS Then September Lock
As of 29 August 2026, Irish SMEs have this weekend to clear July IOSS by Monday 31 August while locking September ROS sequencing: August PAYE on 14 September, bi-monthly VAT on 19 September, and CT1/RCT through 23 September.
Revenue’s Calendar of key dates for tax professionals still 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 Saturday 29 August — with July IOSS two days out on Monday 31 August — this weekend should close IOSS first, then protect September prep slots.
Treat July IOSS 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 weekend through late September
31 August — July IOSS monthly return and payment where the scheme applies (nil returns still required).
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.
Weekend prep checklist before Monday
File or confirm July IOSS before Monday — weekend banking cut-offs often strand payments that looked fine on Friday night.
Lock August payroll runs and employee changes before mid-September leave thins coverage — the 14 September return date arrives faster than it looks.
Reconcile July and August sales and purchase ledgers for the bi-monthly VAT pack while July ROS cash journals are still fresh.
Start 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
Yesterday’s final-weekend checklist still maps the post–23 August turn.
July IOSS still has two days — keep it ahead of September PAYE prep.
August PAYE still has sixteen days to the 14 September return.
December year-end CT1 still has twenty-five days to 23 September.
Bi-monthly July–August VAT still has twenty-one days to 19 September.
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 2026-08-29
- 2.Corporation Tax (CT) payment and filing
Revenue (Irish Tax and Customs) · Accessed 2026-08-29
- 3.When VAT becomes payable
Revenue (Irish Tax and Customs) · Accessed 2026-08-29
Put this into practice
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.
Try AI accounting free