Short answer: in Sri Lanka, SMS reaches almost every phone and costs about LKR 500 to 700 per 1,000 English messages, so it suits OTPs and urgent alerts. WhatsApp reaches around six in ten people with rich media and two-way chat, and utility messages cost about the same as SMS, but marketing messages cost far more. Email is cheapest for long content but weakest for urgency. Most businesses do best with WhatsApp first and SMS as the fallback.
Updated 6 November 2026
- SMS is the only channel that reaches feature phones and people without data, so keep it for OTPs and critical alerts.
- WhatsApp utility and authentication messages cost about US$0.002 each from Meta, close to SMS, but add rich media, buttons and replies.
- WhatsApp marketing messages cost about 35 times more than a promotional SMS, so use them for high-value audiences.
- Email has the lowest cost per message for long content, but fewer people see it quickly.
- A WhatsApp-first, SMS-fallback flow gets the reach of SMS with the engagement of WhatsApp.
Reach: who you can actually get to
DataReportal's Digital 2026 report for Sri Lanka counts 23.3 million people, 30.3 million mobile connections and 13.9 million internet users as of late 2025. That means roughly four in ten people are still not online, so any internet-only channel misses them.
CAL Research figures reported by the Daily Mirror in November 2024 found WhatsApp used by 63% of people, about 14.6 million. It also counted 17.7 million smartphones and tablets against 7.26 million feature phones. Feature phones receive SMS, but not WhatsApp.
Email reach is harder to measure. Most smartphone users have a Google account, but many rarely open the inbox. Email works best for B2B, receipts and long updates, not for messages that must be seen within minutes.
Cost per 1,000 messages in LKR
The table uses Bloomwire's published SMS prices and Meta's WhatsApp rates for Sri Lanka, as shown on our WhatsApp Business API pricing page on 6 November 2026.
| Channel and message type | Price per message | Cost per 1,000 |
|---|---|---|
| SMS, transactional (English, 1 part) | LKR 0.50 | LKR 500 |
| SMS, transactional (Sinhala or Tamil, 2 parts) | LKR 1.00 | LKR 1,000 |
| SMS, promotional (English, 1 part) | LKR 0.70 | LKR 700 |
| WhatsApp, utility (order updates) | US$0.0020, about LKR 0.66 | about LKR 660 |
| WhatsApp, authentication (OTP) | US$0.0020, about LKR 0.66 | about LKR 660 |
| WhatsApp, marketing | US$0.073, about LKR 24.25 | about LKR 24,250 |
| WhatsApp, service replies (customer wrote first) | First 1,000 per number per month free, then about LKR 0.66 | LKR 0 to about LKR 660 |
| Depends on your email service | Usually the lowest per message |
Assumptions: SMS prices include government taxes. WhatsApp figures are Meta's per-message fees converted at LKR 331 per US dollar, excluding your WhatsApp platform plan (from LKR 8,500 a month). Meta fees are paid directly to Meta. Sinhala and Tamil SMS use Unicode, so a 100-character message becomes 2 parts. Rates change; check the pricing page before budgeting.
Unicode matters more than most teams expect. A Sinhala promotion that runs to three SMS parts costs LKR 2.10, three times the English version. Check yours with our free SMS character counter.
WhatsApp also needs a platform plan to send at scale. Bloomwire's WhatsApp plans start at LKR 8,500 a month, then LKR 12,500 and LKR 27,500. Spread across a large monthly volume, that fee adds little per message; for a small sender it is the main cost.
Strengths and limits of each channel
| SMS | |||
|---|---|---|---|
| Works on feature phones | Yes | No | No |
| Needs mobile data or Wi-Fi | No | Yes | Yes |
| Two-way replies | Only with a long number | Yes, built in | Yes, but slow |
| Images, video, PDFs, buttons | No, text only | Yes | Yes |
| Status you can see | Delivery receipt | Sent, delivered and read | Opens, if tracked |
| Verified business identity | Sender ID | Business profile, optional verified badge | Sender domain |
| Opt-in rules | TRCSL opt-out directive; PDPA Part IV pending | Meta requires opt-in naming your business | PDPA Part IV pending |
| Message templates needed | No | Yes, approved by Meta outside 24-hour window | No |
For the rules behind each channel, read our guide to Sri Lanka's PDPA and SMS and WhatsApp marketing.
Which channel for which job
| Use case | Best first channel | Backup | Why |
|---|---|---|---|
| OTP and login codes | SMS | WhatsApp authentication | Works without data and on every phone; WhatsApp OTP costs about the same if the user is on WhatsApp |
| Order and delivery updates | WhatsApp utility | SMS | Same cost as SMS, with tracking buttons and replies |
| Payment reminders and bills | WhatsApp utility with PDF | SMS with short link | Attach the bill; fall back for non-WhatsApp users |
| Promotions to a wide list | SMS promotional | About LKR 0.70 against LKR 24 on WhatsApp | |
| Promotions to high-value customers | WhatsApp marketing | SMS | Images and buttons justify the higher price when order value is high |
| Customer support | The first 1,000 service messages per number each month are free from Meta | ||
| B2B updates and quotes | Long documents, many recipients, records |
WhatsApp first, SMS fallback
You do not have to pick one channel. A fallback flow sends on WhatsApp first and switches to SMS only when WhatsApp cannot deliver. It works best for order updates, reminders and alerts.
- Collect consent for both channels.At checkout or sign-up, ask for permission to message on WhatsApp and SMS, and log it.
- Send the WhatsApp template first.Use an approved utility template with a tracking or payment button.
- Wait for the delivery status.WhatsApp returns sent, delivered and read events through the API.
- Fall back to SMS if not delivered.If there is no delivered status within a set time, such as 5 to 15 minutes, or the number is not on WhatsApp, send a short SMS with a link.
- Route replies to one inbox.Handle WhatsApp replies in a shared team inbox, and give SMS users a link or number to reach you.
- Review the split each month.Track how many messages went by each channel and the cost, then tune the wait time.
Bloomwire runs both channels: our SMS gateway for SMS and the WhatsApp Business API for WhatsApp. See our guide on getting the WhatsApp Business API in Sri Lanka to start.
Frequently asked questions
Is WhatsApp cheaper than SMS in Sri Lanka?
For utility and authentication messages, Meta's fee is about US$0.002, around LKR 0.66, which is close to transactional SMS at LKR 0.50. Marketing messages cost about US$0.073, around LKR 24.25, which is far more than a promotional SMS at LKR 0.70. Since 1 October 2026, service replies are free for the first 1,000 per number each month, then about LKR 0.66 each. Read what changed in WhatsApp pricing from 1 October 2026.
Should I use SMS or WhatsApp for OTPs?
SMS is the safer default because it works without data and on feature phones. WhatsApp authentication messages cost about the same and can work well as a first try for users you know are on WhatsApp. Our guide to OTP over SMS or WhatsApp goes deeper.
How many people use WhatsApp in Sri Lanka?
CAL Research figures reported by the Daily Mirror in 2024 put WhatsApp use at 63% of people, about 14.6 million. DataReportal does not publish a WhatsApp figure for Sri Lanka.
Does SMS still work in Sri Lanka in 2026?
Yes. There are 30.3 million mobile connections and millions of feature phones, and SMS needs no data. It remains the most reliable channel for codes and urgent alerts.
When is email the right choice?
Use email for long content, documents, B2B communication and records, where speed matters less. Pair it with SMS or WhatsApp for anything time-sensitive.
