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Bulk SMS in Thailand: NBTC, Sender Name and PDPA Guide

Bulk SMS Thailand guide: NBTC sender name registration for A2P SMS, PDPA consent, AIS, True and NT operators, and why Thai script caps SMS at 70 characters.

Updated 10 min read

By OmniChannels.ai Editorial Team · Reviewed by BroadNet Messaging Solutions Team

SMS & OTP

Short answer

To send bulk SMS in Thailand, register your alphanumeric sender name (up to 11 characters) so your A2P traffic is not blocked, send marketing only to people who consented under the Personal Data Protection Act, and keep OTPs on a separate sender from promotions. Thai script is Unicode, so one message holds 70 characters (67 per part when split), while English fits 160.

On this page
  1. What rules apply to bulk SMS in Thailand?
  2. What did NBTC change for A2P SMS in 2025?
  3. What does the PDPA require before you send marketing SMS?
  4. How does sender name registration work in Thailand?
  5. Which operators carry SMS in Thailand?
  6. How should you separate OTP and promotional traffic?
  7. How does Thai script affect SMS length?
  8. When should you send?
  9. A worked example: a Chiang Mai coffee chain
  10. What are the common mistakes?
  11. How OmniChannels.ai helps

Key takeaways

  • The National Broadcasting and Telecommunications Commission (NBTC) is the regulator; in August 2025 it published measures requiring that A2P SMS is sent only from registered sender IDs and that operators verify links before delivery.
  • Our regulation data lists alphanumeric sender IDs of up to 11 characters with local script supported, set up through the operators, with a typical lead time of 5 to 10 business days.
  • The Personal Data Protection Act (PDPA) treats a phone number as personal data, so marketing SMS needs a lawful basis, in practice documented consent, and a working opt-out.
  • Thai script is Unicode: 70 characters per single message and 67 per part when split, against 160 and 153 for English text in the GSM 7-bit alphabet.
  • We have not found a regulator-published time-of-day window for promotional SMS in Thailand; schedule promotions for local daytime and keep OTPs and alerts on a separate sender.

This guide is for marketing, e-commerce, fintech and operations teams that want to send business SMS to mobile numbers in Thailand: OTPs, order alerts, reminders and promotions. It explains who regulates what, how sender name registration works, what the Personal Data Protection Act means for consent, which operators carry your traffic and how Thai script changes message length. It is a practical overview, not legal advice; confirm requirements with Thai counsel and the operators before launch.

What rules apply to bulk SMS in Thailand?

Three layers apply: NBTC measures and operator policy, the Personal Data Protection Act (PDPA), and the platform rules of your own provider. None is called a "bulk SMS law", so you assemble the picture from each.

Layer What it covers Where to check
NBTC Telecom regulation, measures on A2P sender IDs and link checks nbtc.go.th
PDPA Lawful basis and consent for processing personal data; data subject rights pdpc.or.th
Operators (AIS, True, NT) Sender name set-up, routes, filtering Your provider

Our regulation data lists the National Broadcasting and Telecommunications Commission as the regulator, records that sender IDs are set up through the operators, and says opt-in must be verifiable with traffic categorised by use case at the time of registration.

What did NBTC change for A2P SMS in 2025?

NBTC measures published in the Royal Gazette on 29 August 2025, titled "Measures to Prevent Technological Crime for Telecommunications Operators", cover A2P SMS. According to Nation Thailand, messages may only be sent from registered sender IDs, and operators must verify the authenticity of links before delivery. The measures took effect on publication, and the report gives no penalties for senders.

In practice this means three things for you:

  • Register before you send. Traffic from an unregistered alphanumeric sender is at risk of being blocked or rewritten by the network.
  • Use clean links. Operators check links, so use your own branded domain, not unknown shorteners. Our guide to SMS link tracking and short links covers safe practice.
  • Stay consistent. Send under the sender name that was registered for that use case.

Rules in this area have been changing quickly. Read the current NBTC announcements and ask your provider which version of the process applies on the day you submit.

What does the PDPA require before you send marketing SMS?

You need a lawful basis for each number, and for marketing that is in practice explicit consent. The PDPA is Thailand's data protection law, modelled on the same principles as the GDPR, and it protects living individuals rather than companies. A mobile number tied to a person is personal data, so collecting it for SMS marketing falls inside the Act. The Personal Data Protection Committee is the supervisory body.

A safe routine follows:

  1. Capture consent with a record: the exact wording shown, the date and time, the channel and the number.
  2. Say who is sending and why at sign-up, for example "Offers from Baan Kafe by SMS".
  3. Honour opt-outs immediately. Our regulation data calls for a STOP keyword and suppression applied automatically; treat deletion requests as opt-outs too.
  4. Keep the suppression list across campaigns and channels.
  5. Do not buy lists. Purchased numbers have no consent trail.

For wording, our opt-in consent generator drafts a consent text, and the guide to opt-in consent across channels shows how to record it. The SMS privacy policy generator helps with the notice.

How does sender name registration work in Thailand?

Business SMS to Thailand uses an alphanumeric sender name of up to 11 characters, and our data says local script is supported. Requirements are set by the operators and confirmed at onboarding. Our published lead time is 5 to 10 business days, which is typical, not guaranteed.

Step What to do
1. Classify Separate service and OTP traffic from marketing, and plan one sender name per use case
2. Choose names Use your registered company or brand name; avoid generic words and names that imitate banks or authorities
3. Prepare documents Company registration papers and an authorisation letter naming the sender and your provider
4. Submit Your provider files with the operators and tracks each approval
5. Test Send an OTP and a promotion to AIS and True handsets before launch

Our sender ID letter generator drafts the authorisation letter, and the Thailand sender ID page shows the current data. To have us prepare and file the registration, see registrations; approval decisions stay with the operators and regulator. For formats, read SMS sender ID types explained.

Which operators carry SMS in Thailand?

Our coverage data lists three mobile codes, all with direct routes, but the market has consolidated.

Operator in our data MCC-MNC Note
AIS 520-03 Advanced Info Service
TrueMove H 520-04 Part of True Corporation
DTAC 520-05 Merged with True in 2023; the code may still appear in reports

True and DTAC completed their merger in early 2023, and the state operator NT (formed from CAT and TOT) is the third network. Read delivery reports per network, not just one blended rate. Our guide to improving SMS delivery rates shows how to diagnose a weak route.

How should you separate OTP and promotional traffic?

Keep OTPs, order alerts and other service messages on their own sender name and route, and promotions on another. Thai guidance from several providers also says marketing traffic should not use a sender registered for transactional use, so a promotion inside an OTP can put your login codes at risk.

Traffic Example Practice
Transactional OTP, payment confirmation, delivery alert No promotion inside; own sender; any hour
Promotional Sale, new product, loyalty offer Consented numbers only; opt-out in the message; daytime schedule
Mixed "Your parcel shipped. Get 10% off your next order" Avoid; the offer makes it promotional

For OTP content and security, read our OTP authentication messages guide.

How does Thai script affect SMS length?

Thai text is sent as Unicode, so one message holds 70 characters and each part of a longer message holds 67. English text without special symbols fits the GSM 7-bit alphabet at 160 and 153. Thai consonants, vowels, tone marks and digits all sit outside that alphabet, and vowel and tone marks count as separate characters, so Thai strings are longer than they look. See GSM-7, UCS-2 and concatenated SMS.

These examples were counted against the limits (Baan Kafe is a synthetic brand):

Message Encoding Characters Parts
Your OTP is 482913. Valid for 5 minutes. Do not share it. Baan Kafe GSM-7 67 1
รหัส OTP ของคุณคือ 482913 ใช้ได้ 5 นาที ห้ามแจ้งรหัสนี้แก่ผู้อื่น - Baan Kafe Unicode 77 2
Baan Kafe: Buy 2 get 1 free this weekend. Details: baankafe.example/p Opt out: baankafe.example/stop GSM-7 100 1
Baan Kafe: ซื้อ 2 แถม 1 สุดสัปดาห์นี้ รายละเอียด baankafe.example/p ยกเลิก baankafe.example/stop Unicode 96 2

A Thai OTP often lands just over 70, so trim wording to stay in one part where you can, for example by shortening the brand suffix. Do not switch to English only to save a part if your audience reads Thai. Check final copy in the SMS character counter, and see SMS character limits and Unicode for other scripts.

When should you send?

We have not found a regulator-published time-of-day window for promotional SMS in Thailand, and our regulation data records none. Some provider guides suggest daytime hours only, which is sensible practice but not a rule we can cite. Agree sending hours with your provider, send promotions in local daytime (UTC+7) and avoid late evenings. OTPs and alerts can go at any hour. The send time planner helps with scheduling.

A worked example: a Chiang Mai coffee chain

"Baan Kafe" (synthetic) has 25 shops and wants OTPs for its app, order alerts and a weekly offer.

  • It registers two sender names, one for service traffic and one for marketing, and tests both on AIS and True handsets.
  • It collects consent in the app and at the till, storing the wording, timestamp and number, and shows an opt-out in every promotion.
  • OTPs are short enough to stay within two Unicode parts, and the team tests whether trimmed copy fits one.
  • The weekly offer goes out in the daytime, checked against the suppression list, and links use the company's own domain.
  • Opt-outs feed one suppression list shared with other channels.

What are the common mistakes?

  • Launching before the sender is registered. Traffic may be blocked or rewritten.
  • Treating consent as optional. A phone number is personal data under the PDPA.
  • Unknown link shorteners. Operators check links before delivery.
  • Forgetting that Thai is Unicode. A message that looks short can run to two or three parts.
  • Mixing OTP and promotion on one sender.
  • Treating lead times as promises. Plan buffer beyond 5 to 10 business days.

How OmniChannels.ai helps

OmniChannels.ai is powered by BroadNet, which has direct routes to AIS and True networks in our coverage data. We prepare and file sender name registration with you, support Thai and English content, and give you per-operator delivery reports, with SMPP 3.4 for high volume. For indicative list prices, see the Thailand SMS pricing page, then book a demo. Learn how SMS fits alongside other channels in WhatsApp vs SMS vs RCS.

Frequently asked questions

Is bulk SMS legal in Thailand?

Yes, businesses send OTPs, alerts and marketing SMS, provided the traffic is sent from a registered sender name and marketing respects the Personal Data Protection Act. There is no single bulk SMS statute, so the rules come from NBTC measures, operator policies and the PDPA. Use a legitimate route and keep proof of consent for every number you promote to.

Do I need to register a sender name in Thailand?

Plan on it. Thai media reported that NBTC measures published in August 2025 allow A2P SMS only from registered sender IDs, and that operators must verify links before delivery. Our data says sender IDs are set up through the operators, with a typical lead time of 5 to 10 business days. Confirm the current process before you launch.

Does the PDPA apply to SMS marketing in Thailand?

Yes for individuals. A mobile number linked to a person is personal data, so you need a lawful basis to process it, and for marketing that is normally explicit consent. The Act protects living individuals, not companies, but a business contact's personal mobile number is still personal data. Keep consent records and honour opt-outs.

Which operators carry SMS in Thailand?

Our coverage data lists AIS, TrueMove H and DTAC with direct routes. DTAC merged with True in 2023 and is part of True Corporation, so in practice you reach the market through AIS and True plus the state operator NT. Ask your provider to show per-operator delivery reports so you can see each network separately.

Does Thai text use Unicode?

Yes. Thai letters are not in the GSM 7-bit alphabet, so a Thai message is sent as Unicode and holds 70 characters, or 67 per part when split. Vowel and tone marks are separate characters and count too. English text fits 160 characters. Check the final copy in a character counter before sending a campaign.

What time can I send promotional SMS in Thailand?

We have not found a regulator-published time-of-day window for promotional SMS in Thailand, and our regulation data records none. Send promotions in local daytime (UTC+7), avoid late evenings and early mornings, and agree hours with your provider. OTPs and alerts are time-critical and can go at any hour.

Sources

  1. National Broadcasting and Telecommunications Commission (NBTC)
  2. New NBTC law tightens rules on SIMs, SMS and foreign calls effective immediately, Nation Thailand
  3. Personal Data Protection Committee (PDPC), Thailand
  4. True and Dtac merge to create biggest telco in Thailand, RCR Wireless
  5. 3GPP TS 23.038: Alphabets and language-specific information

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