Introduction
SMS marketing delivers results that email simply cannot match. With a 98% open rate, 19% average click-through rate, and 90-second average read time, SMS is the highest-ROI channel for reaching opted-in customers.
But the power of SMS comes with responsibility. Sending to unconsented recipients, using misleading sender IDs, or spamming subscribers will damage your brand and may trigger regulatory action from the ICO.
This guide covers the best practices that leading UK brands use to run compliant, effective SMS campaigns in 2026.
1. Build a Consented List
Everything starts with consent. Under PECR (Privacy and Electronic Communications Regulations), you must have explicit opt-in consent before sending marketing SMS to UK consumers — unless the soft opt-in (existing customer) rule applies.
How to build a consented list:
- •Add an SMS opt-in checkbox to your checkout flow (separate from email)
- •Run keyword-based opt-in campaigns ("Text JOIN to 60777 for exclusive offers")
- •Offer a lead magnet in exchange for SMS consent
- •Import existing email subscribers who have separately consented to SMS
What to avoid:
- •Pre-ticked consent boxes
- •Bundling SMS consent with Terms & Conditions acceptance
- •Purchasing phone number lists (these have no valid consent)
2. Personalise Every Message
Generic broadcast SMS underperforms. Personalised SMS — using the recipient's name, referencing their last purchase, or acknowledging their location — significantly outperforms generic blasts.
The BulkSMSRates API supports merge fields for batch personalisation. Example:
"body": "Hi {{first_name}}, your {{product_name}} is ready to collect at {{store}}."
At scale, this drives 35% higher engagement than generic messages.
3. Timing Is Everything
Best times to send marketing SMS in the UK (based on aggregated campaign data):
| Day | Best Window | Avoid |
|---|---|---|
| Monday | 12pm–2pm | 8am–9am |
| Tuesday–Thursday | 10am–12pm | After 8pm |
| Friday | 12pm–3pm | Friday evening |
| Saturday | 10am–12pm | Before 9am |
| Sunday | Avoid entirely | — |
For retail: Flash sale SMS sent between 10am–12pm generate 40% more conversions than evening sends.
4. Keep It Short and Actionable
SMS is not email. Keep messages under 160 characters (1 segment) where possible. Every word must earn its place.
High-converting SMS formula:
- 1.Brand name (if not in sender ID)
- 2.Benefit/offer (specific, time-sensitive)
- 3.Call to action (short URL)
- 4.Opt-out (STOP to 12345)
- •Add them to your suppression list immediately (within 24 hours)
- •Never contact them again for marketing purposes
- •Honour the opt-out across all SMS communications from your brand
- •Send time (morning vs lunchtime)
- •Offer type (percentage discount vs free shipping)
- •CTA wording ("Shop now" vs "Claim your offer")
- •Message length (1 segment vs 2 segments)
Example:
"ACME: 30% off all orders ends midnight. Shop: acme.com/sale. Reply STOP to opt out."
That's 80 characters — clear, compliant, and compelling.
5. Honour Opt-Outs Immediately
Every marketing SMS must include an opt-out mechanism. When someone replies STOP:
BulkSMSRates automatically processes STOP replies and adds numbers to your suppression list.
6. Test Before You Send
Run A/B tests on:
Even small improvements — 2–3% better click-through — compound significantly at scale.
Conclusion
SMS marketing works because it's immediate, personal, and respectful of the recipient's time when done right. Build consented lists, personalise messages, time sends carefully, and always include opt-outs. These practices will consistently deliver 15–25% conversion rates for UK SMS campaigns in 2026.