If you own rental property in Cardiff and your annual income from property exceeds £50,000, you are already operating under Making Tax Digital (MTD) for Income Tax Self Assessment. The regime went live in April 2026, and the first major quarterly filing deadline of 7 August 2026 has passed. But the next one is approaching fast.
The 7 November 2026 deadline is your second quarterly update submission to HMRC, and for many Cardiff landlords it will be the first real test of whether your digital record-keeping systems are working as they should.
This guide, from Belvoir Cardiff, breaks down exactly what you need to do, what it means for your occupation contracts under the Renting Homes (Wales) Act 2016, and how Cardiff’s buoyant rental market makes getting this right more important than ever.
Why this deadline matters for Cardiff landlords specifically
Cardiff’s private rental sector is one of the most active in Wales. Average rents across the city now sit at £1,157 per month, up 4.8% year-on-year, driven by sustained demand from students, NHS and healthcare professionals based at University Hospital Wales and Cardiff and Vale University Health Board, and a growing cohort of young corporate professionals drawn to the city’s expanding financial and tech sectors.
For landlords operating in high-yield postcodes such as CF24, covering Cathays and Roath, gross yields are consistently running between 6.5% and 8%. These are among the strongest returns available in any Welsh city, and they reflect the sheer volume of occupation contracts being signed and renewed across the area.
With rental incomes at these levels, many Cardiff landlords crossed the £50,000 MTD threshold well before April 2026. That means your obligations are live, your quarterly updates are due, and the 7 November 2026 deadline is not optional.
Understanding Making Tax Digital for Income Tax Self Assessment
What the regime requires
MTD for Income Tax Self Assessment (MTD for ITSA) replaces the traditional annual Self Assessment tax return for landlords who meet the income threshold. Instead of one annual submission, you now submit four quarterly updates to HMRC each tax year, followed by a final end-of-period statement and a tax return declaration.
The four quarterly deadlines for the 2026/27 tax year are:
- 7 August 2026 (Quarter 1: April to June)
- 7 November 2026 (Quarter 2: July to September)
- 7 February 2027 (Quarter 3: October to December)
- 7 May 2027 (Quarter 4: January to March)
The 7 November 2026 deadline covers income and expenses from July, August and September 2026. If your records are not being maintained digitally and updated in real time, you are already behind.
Who is affected right now?
From April 2026, landlords with gross income from property and/or self-employment exceeding £50,000 per year are mandated to comply. Given that average rents in Cardiff now exceed £1,157 per month, a landlord with just four or five properties in Roath, Pontprennau or Llandaff could easily clear this threshold.
Landlords with income between £30,000 and £50,000 must prepare now too. Their mandatory MTD transition date is April 2027, which is less than six months away.
Digital record-keeping: what you must do
Using compatible software
HMRC requires that all records are kept and submitted using MTD-compatible software. This is not a spreadsheet in the traditional sense, though bridging software can connect certain spreadsheets to HMRC’s systems. Popular options used by Cardiff landlords include QuickBooks, Xero, FreeAgent, and landlord-specific tools such as Hammock or Landlord Studio.
Speak to your accountant about which platform integrates best with your existing setup. Belvoir Cardiff works closely with landlords across the city and can point you towards trusted local advisers if needed.
What income and expenses to record
Every quarter, your digital records must capture:
- All rental income received from each occupation contract, whether that is a fixed-term or periodic occupation contract under the Renting Homes (Wales) Act 2016.
- All allowable expenses, including letting agent fees, repairs and maintenance, insurance premiums, mortgage interest (subject to the current tax credit rules), and professional service costs such as legal fees relating to your occupation contracts.
- Any other property-related income, such as payments for storage, parking, or additional services provided to contract holders.
Under the Renting Homes (Wales) Act 2016, occupation contracts have replaced traditional assured shorthold tenancies in Wales. Your records must reflect the correct legal framework, particularly if you are managing multiple contract holders across a portfolio in areas such as Cardiff Bay, Grangetown or Canton.
Submitting your quarterly update
Once your records for the quarter are complete, your MTD-compatible software will allow you to submit the quarterly update directly to HMRC. The submission summarises your income and expenses for the period. It is not a tax payment, but it feeds into your cumulative tax position for the year.
Missing the 7 November 2026 deadline will trigger HMRC’s new points-based penalty system. Accumulate enough points and financial penalties follow. Do not leave this until the last week of October.
The Welsh legal context: occupation contracts and your compliance obligations
Cardiff landlords operate in a distinct legal environment. The Renting Homes (Wales) Act 2016, fully enacted from December 2022, fundamentally changed the structure of residential letting in Wales.
All residential agreements in Wales are now occupation contracts, not tenancies. Your contract holders have specific rights under this legislation, including the right to a written occupation contract, a minimum notice period of six months for no-fault eviction under a Section 173 notice, and protections around property fitness for human habitation.
For MTD purposes, this distinction matters. Your digital records should reference occupation contracts and contract holders accurately, particularly when logging legal costs, notice-related expenses, or any income adjustments arising from disputes or contract variations.
If you manage a portfolio across CF24, CF10 (Cardiff city centre), CF11 (Pontcanna and Canton) or CF14 (Whitchurch and Rhiwbina), ensuring your records correctly categorise each occupation contract by property is essential for accurate quarterly reporting.
Preparing for April 2027 if you are not yet mandated
If your rental income currently sits between £30,000 and £50,000, perhaps because you hold two or three properties in areas like Splott, Adamsdown or Llanishen, your MTD start date is April 2027. That is not far away.
Now is the time to choose your software, begin digitising your records, and speak to an accountant familiar with Welsh property law and MTD compliance. Starting early means the transition will be seamless rather than stressful.
Belvoir Cardiff strongly encourages all landlords in this income bracket to treat preparation as an immediate priority, not a 2027 concern.
How Belvoir Cardiff supports landlords through compliance changes
Managing occupation contracts, maintaining compliant properties, and now navigating MTD quarterly filings represents a significant administrative load, particularly for portfolio landlords managing multiple contract holders across Cardiff’s diverse neighbourhoods.
Belvoir Cardiff provides full property management services that take the day-to-day burden off landlords, from rent collection and maintenance coordination to contract administration under the Renting Homes (Wales) Act 2016. Our local knowledge of the Cardiff market, from the student-heavy streets of Cathays to the family-friendly avenues of Cyncoed, means we understand the pressures you face.
Take action before 7 November 2026
The November deadline is weeks away. If you have not yet submitted your Quarter 1 update, or if your digital records for July to September are incomplete, act now.
Here is a simple checklist before the deadline:
- Confirm your MTD-compatible software is active and connected to HMRC.
- Log all rental income received from each occupation contract for July, August and September 2026.
- Categorise and record all allowable expenses for the same period.
- Review your records for accuracy, particularly if you have had any contract holder changes, void periods or maintenance works during the quarter.
- Submit your quarterly update via your software before 7 November 2026.
Belvoir Cardiff is here to help you navigate every aspect of managing your Cardiff rental portfolio, from compliance with Welsh legislation to maximising the return on your investment in one of Wales’s most resilient property markets.
To find out what your Cardiff rental property is worth in today’s market, book a free rental valuation with Belvoir Cardiff today. Our team will provide an accurate, data-led assessment based on current demand across your postcode.
For questions about property management, occupation contracts, or how MTD affects your portfolio, contact Belvoir Cardiff directly. Our team is ready to support landlords of all portfolio sizes, whether you hold one property in Roath or a multi-unit portfolio across the city.