---
title: "Bulk SMS in Uruguay: URSEC, Law 18.331 and Sender ID Guide"
description: "Bulk SMS Uruguay guide (SMS masivos): URSEC, Law 18.331 consent and the right to block advertising, Antel, Tigo and Claro, sender set-up and Spanish accents."
canonical: "https://omnichannels.ai/blog/bulk-sms-uruguay-guide/"
language: "en"
updated: "2026-11-06"
publisher: "BroadNet Technologies"
brand: "OmniChannels.ai"
category: "sms"
primaryQuery: "bulk sms uruguay"
keywords: ["bulk sms uruguay", "sms masivos uruguay", "ley 18.331 sms", "ursec sms", "sender id uruguay", "antel tigo claro sms", "urcdp publicidad sms"]
published: "2026-11-06"
author: "OmniChannels.ai Editorial Team"
reviewer: "BroadNet Messaging Solutions Team"
readingMinutes: 9
answer: "To send bulk SMS in Uruguay (SMS masivos), use a provider with routes to Antel, Tigo and Claro, confirm your sender set-up with the operators, and message only people who gave prior, express and informed consent under Law 18.331. The law also lets people ask at any time for their data to be removed or blocked from advertising lists. Keep consent records, offer a clear opt-out, and expect accented Spanish to use Unicode at 70 characters."
takeaways: ["URSEC is the telecom regulator in our regulation data; sender requirements are set by the operators, with a typical lead time of 5 to 10 business days, and formats are alphanumeric where supported or numeric long codes and short codes.", "Law 18.331 on personal data protection requires consent that is free, prior, express and informed (article 9), and article 21 lets people request removal or blocking of their data for advertising at any time; the data authority is the URCDP.", "Three networks appear in our coverage data, all with direct routes: Antel (748-01), Tigo Uruguay (748-07) and Claro Uruguay (748-10). Tigo took over the former Movistar business, a deal Millicom reported as completed on 7 October 2025.", "Spanish letters such as e with an acute accent and n with a tilde fit the GSM 7-bit alphabet, but a, i, o and u with an acute accent do not, so a single one switches the message to Unicode at 70 characters (67 per part).", "We found no regulator-published time-of-day window for promotional SMS in Uruguay; schedule promotions for local daytime and keep OTPs and alerts on a transactional route."]
faq: 
  - q: "Is bulk SMS legal in Uruguay?"
    a: "Yes. Businesses send OTPs, alerts and marketing SMS, provided they use a legitimate route, hold consent for marketing and honour opt-outs. No single statute is called a bulk SMS law, so the rules come from URSEC, the operators and the personal data law. Confirm the details with Uruguayan counsel before a large campaign."
  - q: "Do I need consent to send promotional SMS in Uruguay?"
    a: "Plan on documented consent. Law 18.331 sets the principle of prior, informed consent, and the data authority has applied it to unsolicited messages. Our regulation data also calls for verifiable opt-in with consent records kept. Store the wording, the timestamp, the channel and the number for every opt-in."
  - q: "Can people ask to be removed from advertising lists?"
    a: "Yes. Article 21 of Law 18.331 says that, for data used in advertising or commercial prospecting, the holder may at any time request the removal or blocking of their data. Treat any such request as binding, apply it to every campaign and channel, and keep a suppression list."
  - q: "Can I use an alphanumeric sender ID in Uruguay?"
    a: "Our regulation data says alphanumeric IDs are available where supported, with numeric long codes and short codes as alternatives, and that the operators set the requirements. Support can differ by operator, so test the sender on Antel, Tigo and Claro handsets before launch. We can prepare and file the registration with you."
  - q: "Why does my Spanish SMS split into two parts?"
    a: "Letters such as a, i, o and u with an acute accent are not in the default GSM 7-bit alphabet, so one of them switches the whole message to Unicode, which holds 70 characters (67 per part). Letters such as e with an acute accent and n with a tilde are inside it. Test final copy in a character counter."
  - q: "How long does sender registration take in Uruguay?"
    a: "Our published lead time for Uruguay is 5 to 10 business days. That is a typical range, not a promise. Operators review the application, and missing company documents can add time. Build it into your launch plan and use our team to prepare and file the registration."
sources: 
  - title: "URSEC, Unidad Reguladora de Servicios de Comunicaciones"
    url: "https://www.gub.uy/unidad-reguladora-servicios-comunicaciones/"
  - title: "Ley 18.331, Protección de Datos Personales, IMPO"
    url: "https://www.impo.com.uy/bases/leyes/18331-2008"
  - title: "URCDP, Unidad Reguladora y de Control de Datos Personales"
    url: "https://www.gub.uy/unidad-reguladora-control-datos-personales/"
  - title: "Millicom (Tigo) completes acquisition of Telefónica in Uruguay"
    url: "https://finviz.com/news/185853/millicom-tigo-completes-acquisition-of-telefonica-in-uruguay-strengthening-its-regional-footprint-in-south-america"
  - title: "3GPP TS 23.038: Alphabets and language-specific information"
    url: "https://www.3gpp.org/dynareport/23038.htm"
---

# Bulk SMS in Uruguay: URSEC, Law 18.331 and Sender ID Guide

Canonical: https://omnichannels.ai/blog/bulk-sms-uruguay-guide/
Language: en
Publisher: OmniChannels.ai by BroadNet Technologies

This guide is for retail, banking, education and service teams that want to send business SMS to mobile numbers in Uruguay: OTPs, delivery alerts, reminders and promotions. It explains which rules apply, what Law 18.331 means for marketing, how sender set-up works and how Spanish accents change message length. It is a practical overview, not legal advice; confirm requirements with Uruguayan counsel and the operators before you launch.

## What rules apply to bulk SMS in Uruguay?

Three layers apply: telecom regulation and operator policy, personal data law, and your own consent records. None is a single "bulk SMS law", so you assemble the picture from each.

| Layer | What it covers | Where to check |
|---|---|---|
| URSEC and the operators (Antel, Tigo, Claro) | Telecom regulation, sender set-up, routes, filtering | [URSEC](https://www.gub.uy/unidad-reguladora-servicios-comunicaciones/) |
| Law 18.331 and the URCDP | Consent, advertising data, data subject rights | [IMPO](https://www.impo.com.uy/bases/leyes/18331-2008), [URCDP](https://www.gub.uy/unidad-reguladora-control-datos-personales/) |
| Your own records | Proof of when and how each number agreed | Your CRM or consent log |

Our regulation data names URSEC (Unidad Reguladora de Servicios de Comunicaciones) as the regulator and records that sender requirements are set by the operators, so the rule that matters on launch day is the one your operator route enforces.

## What does Law 18.331 require before you send?

You need consent that is free, prior, express and informed. Article 9 of Law 18.331 makes that the basis for processing personal data, with exceptions such as data from public sources or data needed for a contract. A promotional SMS to a customer who never agreed to marketing does not fit those exceptions in any simple way, so treat opt-in as required for promotions.

Article 21 deals with data used for advertising and commercial prospecting. In the text we reviewed, the holder can at any time ask for their data to be removed or blocked. The URCDP, the data authority created by the law, has issued resolutions that apply the prior informed consent principle to unsolicited messages, so complaints do reach it.

A safe routine follows:

1. **Capture consent with a record:** the exact wording shown, the date and time, the channel and the number.
2. **Name the sender and the purpose** at sign-up, for example "Ofertas de Tienda Río por SMS".
3. **Honour removal requests at once** and keep one suppression list across campaigns and channels.
4. **Keep evidence** so you can answer a complaint.
5. **Do not buy lists.** Purchased numbers have no consent trail.

Our regulation data adds that opt-in must be verifiable and that records are kept as the local data protection law requires. Our [opt-in consent generator](/tools/opt-in-consent-generator/) drafts wording, and the guide to [opt-in consent across channels](/blog/opt-in-consent-multichannel-campaigns/) shows how to record it. See also [opt-in](/glossary/opt-in/) and [opt-out](/glossary/opt-out/).

## How do sender IDs and short codes work in Uruguay?

Uruguay supports alphanumeric sender IDs where the operator supports them, plus numeric long codes and short codes. The operators set the requirements and the process is confirmed at onboarding. Our published lead time is 5 to 10 business days; treat it as typical, not guaranteed.

| Step | What to do |
|---|---|
| 1. Classify | Decide which traffic is transactional (OTP, alerts) and which is promotional, and plan one sender for each |
| 2. Choose names | Use your registered business or brand name; avoid names that imitate banks, operators or public bodies |
| 3. Prepare documents | Company registration papers and an authorisation letter naming the senders and your provider |
| 4. Submit | Your provider files with the operators; track each approval |
| 5. Test | Send an OTP and a promotion to Antel, Tigo and Claro handsets and check what each shows |

Our [sender ID letter generator](/tools/sender-id-letter-generator/) drafts the letter, and you can check the position with the [sender ID checker](/tools/sender-id-checker/) or the [Uruguay sender ID page](/sender-id/uruguay/). If you want us to prepare and file the registration with you, see [registrations](/services/registrations/); approval decisions stay with the operators and regulators. For formats, read [SMS sender ID types explained](/blog/sms-sender-id-types-explained/), and see [short code](/glossary/short-code/) and [long code](/glossary/long-code/).

## Which operators carry SMS in Uruguay?

Three mobile networks appear in our coverage data, each with a direct route.

| Operator | MCC-MNC |
|---|---|
| Antel | 748-01 |
| Tigo Uruguay | 748-07 |
| Claro Uruguay | 748-10 |

Readers still search for "Movistar Uruguay". Millicom, which runs the Tigo brand, reported that it completed the purchase of Telefónica's Uruguay mobile business on 7 October 2025, so older documents may use a different operator name.

Read delivery reports per operator, not as one blended figure. A healthy total can hide a weak network, and our guide to [improving SMS delivery rates](/blog/sms-not-delivered-improve-delivery-rate/) shows how to diagnose it.

## How should you separate OTP and promotional traffic?

Keep OTPs, order alerts and service messages on their own sender and route, and promotions on another. A promotion inside an OTP puts login codes at risk if the promotional route is filtered or a customer complains.

| Traffic | Example | Practice |
|---|---|---|
| Transactional | OTP, payment confirmation, delivery alert | No offer inside; own sender; any hour |
| Promotional | Sale, new product, loyalty offer | Consented numbers only; opt-out in the message; daytime schedule |
| Mixed | "Tu pedido salió. Tienes 10% de descuento en el próximo" | Avoid; the offer makes it promotional |

For OTP design and security, read our [OTP authentication messages guide](/blog/otp-authentication-messages-guide/).

## How do Spanish accents affect SMS length?

Plain Spanish fits the 160-character GSM 7-bit alphabet only if every character is in it. The alphabet includes the e with an acute accent, the n with a tilde and the marks for inverted question and exclamation, but not the acute-accented a, i, o or u, so a single "código" or "sábado" turns the whole message into Unicode with 70 characters (67 per part). See [GSM-7](/glossary/gsm-7/), [Unicode SMS](/glossary/unicode-sms/) and [concatenated SMS](/glossary/concatenated-sms/).

| Encoding | Single message | Per part when concatenated |
|---|---|---|
| GSM 7-bit | 160 characters | 153 |
| Unicode (UCS-2) | 70 characters | 67 |

These examples were counted against the limits:

| Message | Encoding | Characters | Parts |
|---|---|---|---|
| `Tienda Rio: tu codigo es 731904. No lo compartas con nadie.` | GSM-7 | 59 | 1 |
| `Tienda Rio: tu pedido 5521 llega mañana entre las 9 y las 12 h.` | GSM-7 | 63 | 1 |
| `Tienda Rio: 3x2 en camisetas hasta el viernes. Detalles: tiendario.example/o Responde STOP para no recibir mas.` | GSM-7 | 111 | 1 |
| `Tienda Río: 3x2 en camisetas hasta el viernes. Detalles: tiendario.example/o Responde STOP para no recibir más.` | Unicode | 111 | 2 |
| `Tienda Rio: 3x2 en camisetas hasta el viernes ¡No te lo pierdas! Detalles: tiendario.example/o Responde STOP para no recibir mas.` | GSM-7 | 129 | 1 |

Row 2 shows that "mañana" costs nothing because the tilde n is in the alphabet, and row 5 shows the inverted exclamation mark is safe too. Row 4 shows the cost of "Río" and "más": two acute-accented vowels turn a one-part message into two. Many brands drop accents in OTPs and alerts and keep correct spelling in campaigns where a second part is acceptable. Check final copy in the [SMS character counter](/tools/sms-character-counter/); see [SMS character limits and Unicode](/blog/sms-character-limits-unicode-arabic/).

## How do opt-outs work?

Offer a one-step opt-out in every promotional SMS and apply it to all channels. Our regulation data lists STOP as a keyword honoured network-wide. It also lists "SAIR", a Portuguese word that does not suit a Uruguayan audience, so write a clear Spanish instruction and test the keyword you choose before launch. Do not send a promotion to anyone who has asked to stop or to be blocked from advertising.

## When should you send?

We have not found a regulator-published time-of-day window for promotional SMS in Uruguay, and our regulation data records none. Agree sending hours with your provider, send promotions in local daytime (Uruguay is UTC-3 all year) and avoid late evenings. OTPs and alerts can go at any hour. The [send time planner](/tools/send-time-planner/) helps schedule campaigns, and [SMS marketing rules by country](/blog/sms-marketing-rules-by-country/) compares hours across markets.

## A worked example: a Montevideo clothing shop

"Tienda Río" (synthetic) has 8 shops and an online store, and wants OTPs, delivery alerts and a monthly offer.

- It sets up two senders, one for transactional and one for promotional traffic, and tests both on Antel, Tigo and Claro.
- It collects consent at checkout and in store, storing the wording, timestamp and number, and shows "Ofertas por SMS" with a clear opt-out.
- OTPs and alerts use short copy without acute accents so they stay at one part.
- The monthly offer is checked against its suppression list, scheduled for local daytime and sent with correct spelling, accepting two parts.
- Removal requests from replies and the website feed one list that also covers WhatsApp and email.

## What are the common mistakes?

- **No consent evidence.** Without a timestamp and source you cannot answer a complaint to the URCDP.
- **Ignoring removal requests.** Article 21 gives people the right to ask at any time.
- **Look-alike sender names** that imitate banks, operators or public bodies.
- **Ignoring encoding.** One accented vowel turns a 160-character message into a 70-character one.
- **Mixing OTP and promotion on one sender.**
- **Using the Portuguese keyword.** "SAIR" means nothing to Spanish speakers.
- **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 Antel, Tigo and Claro in our coverage data. We prepare and file sender registration with you, support Spanish content, scheduled sends and WhatsApp with SMS fallback, and give you per-operator delivery reports, with SMPP 3.4 for high volume. For indicative list prices, see the [Uruguay SMS pricing page](/sms-pricing/uruguay/), then [book a demo](/demo/). Small team? Our [SMS marketing guide for small businesses](/blog/sms-marketing-small-business-guide/) covers the basics.