Can I serve the notice earlier than 90 days?

Yes. Serving earlier is always allowed; it simply means a longer gap before the new rent applies.

Does the 90 days start when the tenant receives it?

Service is what counts, and for post that is the date of posting. But because delivery is outside your control, allowing a few extra days protects the notice.

Five ways landlords get the 90-day notice period wrong

Updated 2026-09-20 · Ireland · applies from 1 March 2026

Short answer

The 90 days run from the date the notice is signed and served, not from the date you decided on the increase. Ninety days is ninety days, not three months. And the effective date must also satisfy the 12-month interval since the rent was last set — whichever constraint lands later is the one that governs.

Counting from the wrong date, forgetting the 12-month interval, serving before the CPI is published — the errors that make a rent review unenforceable.

1. Counting 90 days from the wrong date

The clock starts on the date the notice is signed and served, not the date you decided on the increase or the date you posted it without proof.

2. Treating 90 days as three months

Ninety days is ninety days. From 19 September that is 18 December, not 19 December. Off-by-one errors here invalidate the notice.

3. Ignoring the 12-month interval

Ninety days of notice does not help if the rent was set only eight months ago. The effective date must satisfy both constraints, and the later one governs.

4. Using a stale CPI figure

The index is revised and published monthly with a lag. Quoting a month that had not been published on the date of service undermines the calculation.

5. Posting it and assuming 90 days

The date of posting counts as service, but delivery is outside your control. A postal delay can leave the tenant holding the notice for less than 90 days, which is exactly the kind of detail a dispute turns on. Allow a few days more than the minimum when you post.

Questions

Can I serve the notice earlier than 90 days?: Yes. Serving earlier is always allowed; it simply means a longer gap before the new rent applies.
Does the 90 days start when the tenant receives it?: Service is what counts, and for post that is the date of posting. But because delivery is outside your control, allowing a few extra days protects the notice.

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