Quick answer
Not straight away. HMRC decides whether you need MTD for Income Tax from the qualifying income on your tax returns, so a new business only brings you in once a return shows you’re over the threshold. If you’re already in MTD and start a new income source, you add it to your HMRC account, and quarterly updates for it start after it has been included in a tax return.
Key facts
New businesses don’t need MTD immediately
HMRC uses your latest tax return to decide
Already in MTD? Add the new source in HMRC online services
Updates for a new source start after it’s on a tax return
If you’re not in MTD yet
Register for Self Assessment as usual. Once a tax return shows qualifying income over the threshold, HMRC writes to tell you to start MTD from the following tax year. You can also choose to join voluntarily.
If you’re already in MTD
Add the new income source in your HMRC online services account, or ask your agent to, before you submit the tax return that includes it.
Keep normal records for it until it has appeared on a tax return.
From then on, create digital records and send quarterly updates for it. You can choose to start quarterly reporting from day one instead.
What counts as a new income source
A new sole trade
Your first UK rental property
Your first overseas rental property
Another UK property isn’t a new source, because it joins your existing UK property business. See MTD with several rental properties.