When Is It Too Late to Message a Customer? The UK Rules, Plainly
The short answer
No UK law sets the hours a business may send a text or a WhatsApp message. Plenty of blogs say otherwise, often quoting "9am to 8pm" or "8am to 9pm" as if a regulator had written it down. We went to the primary sources in September 2026 to check, because our own follow-up messages needed a sending window, and the rules turned out to say much less than the blogs claim.
What they do say is worth knowing, because "no law" is not the same as "any time".
What each rule actually says
| Source | What it says about time of day | Covers |
|---|---|---|
| PECR (the Privacy and Electronic Communications Regulations 2003) | Nothing. It governs consent and the right to opt out, not hours. | Marketing by text, email and messaging |
| DMA Code (2025), Rule 1.4 | Take "all reasonable steps" so customers do not get commercial calls or SMS "at times considered antisocial". No hours are named. | Members of the Data & Marketing Association |
| Old DMA Code, 3rd edition (superseded) | No calls between 9pm and 8am Monday to Friday, or 9pm and 9am at weekends, unless invited. | Telephone calls only |
| FCA, MCOB 3A.4.2G | An "unsocial hour" usually means Sunday, or before 9am or after 9pm on other days. | Financial promotions for mortgages only |
| Ofcom persistent misuse policy (2016) | Misuse at unsociable hours is treated as more harmful, but Ofcom does "not prescribe those hours". | Phone calls |
So the only specific hours anywhere in UK rules belong to mortgage promotions and to a retired telephone code. The DMA's current rule is the closest thing to a general standard, and it asks you to judge what your audience would consider antisocial.
The "9am to 8pm" figures you see quoted come from SMS marketing vendors' own guides (Klaviyo and TextMagic among them, 2025). They are reasonable house rules for bulk marketing. They are not law.
Replying is different from messaging first
Every rule above is about contact the business starts. When a parent messages you at 10.40pm asking whether Saturday's class has space, answering them straight away is service, not marketing. They chose the hour. The courtesy question only arises for messages you initiate: a follow-up on an enquiry that went quiet, a reminder, a check-in after a trial.
For those, consent matters more than the clock. A parent who asked you about classes has usually opened the door to a relevant follow-up, and our guide to PECR and follow-up messages covers where that door ends.
The constraint that bites on WhatsApp
On WhatsApp, the practical limit is not a regulator but the people you message. A business number carries a quality rating built from the last seven days of customer feedback, including how often people block it and why. A number's messaging limit rises only while its messages are rated well, and Meta can limit or offboard a business that draws too much negative feedback. Meta sets no time-of-day rule, but a message that wakes someone at 6am is the kind most likely to be blocked.
WhatsApp also shapes timing in a second way. After a customer's last message, a business has 24 hours to send ordinary written messages. After that, only pre-approved template messages are allowed. A personal follow-up has to land inside that day, which is why the hour a conversation stalls matters so much.
The window we chose, and why
Our assistant answers customers at any hour. Everything it starts on its own has a window:
- The follow-up on a quiet enquiry: 8am to 9pm. These are the outer limits of the old DMA weekday calling hours. We widened it from 9am to 8pm for a measured reason: under the old window, a follow-up for a conversation that went quiet overnight or in the morning could not go out inside WhatsApp's 24 hours, so it never went at all. In two weeks at one customer, that left 65 quiet enquiries without their follow-up. With the wider window, and a send at 8.59pm that evening when the next morning would be too late, every quiet enquiry now gets one. Those parents wrote back far less often than the ones who got one (the numbers are here).
- Reminders, check-ins and review requests: 9am to 8pm. These are tied to a date, not to a 24-hour limit, so they gain nothing from going earlier or later.
We looked at sending the follow-up at exactly the same delay whatever the hour, and set it aside. It would have put the busiest morning's families on a message at half past five, and a block from a woken parent counts against the whole number, not just one conversation.
A sensible rule for your own messages
- Answer anyone who writes to you, whenever they write.
- For messages you start, pick a window your customers would call reasonable and write it down. On weekdays, 8am to 9pm sits inside every hour limit in the table apart from the mortgage rule's 9am start.
- Be more careful at weekends and on Sundays if your customers would be. The old DMA code started weekend calls at 9am, and the mortgage rule usually treats Sunday as unsocial.
- Keep it to one follow-up on a quiet enquiry, and stop the moment anyone asks you to.
Frequently Asked Questions
What time can a business text you in the UK?
No UK law sets hours for business texts or WhatsApp messages. PECR governs consent, not time of day. The DMA Code asks marketers to avoid "antisocial" times without naming hours. The only specific hours in UK rules are the FCA's for mortgage promotions, where an "unsocial hour" usually means before 9am, after 9pm or on a Sunday.
Is it illegal to send marketing messages after 8pm in the UK?
No. The 8pm cut-off quoted online comes from SMS vendors' own best-practice guides, not from PECR or the ICO. Consent rules still apply at every hour, and messaging at antisocial times can breach the DMA Code for its members and draw blocks that damage a WhatsApp number's quality rating.
Can I reply to a customer's WhatsApp message late at night?
Yes. Answering a message the customer sent is service, and they chose the hour. The courtesy rules above concern messages the business starts, such as follow-ups and reminders.
What window does Conciergr use?
Replies go out at any hour. A follow-up on a quiet enquiry goes out between 8am and 9pm local time; reminders, check-ins and review requests between 9am and 8pm.
Conciergr answers your enquiries in seconds, around the clock, from documents you own — and your team keeps using WhatsApp exactly as before.
Join the waitlist