How Do USSD Codes Work

Last checked: 26 June 2026

Quick Answer

USSD codes work by opening a live text session between your cellphone and a service on the mobile network. You dial a short code, usually in a format like *...#, press call or send, and a text menu or response appears on your screen. You then reply with numbers or short prompts until the session ends.

There is no single USSD code for “how do USSD codes work”. USSD is a method, not one universal service. Each code belongs to a specific mobile network, bank, public-service provider, subscription service, or account function. Before using any code, verify it with the official provider.

USSD is useful in South Africa because it can work on basic phones and smartphones, and it usually does not require mobile data or an app. GSMA explains that USSD does not require an internet connection or data and needs only a GSM connection, which is why it remains useful for low-data and basic-phone access. (GSMA)

Step-by-Step Instructions

1. You dial a USSD code

A USSD journey starts in your phone dialler. You type the code exactly as shown by the official provider and press call or send. Many USSD codes use symbols such as * and #, but the exact code depends on the provider and service.

For example, a network may publish USSD options for airtime, balances, bundles, account settings, or subscriptions. MTN South Africa describes USSD codes as a way to find information, request services, manage your account, recharge, and sign up for subscriptions. (MTN)

Do not guess a code. Do not use a code from a WhatsApp message, Facebook comment, screenshot, or forwarded SMS unless you can confirm it on the official provider’s website, app, branch material, or verified support channel.

2. Your phone sends the request through the mobile network

When you send the code, your phone does not open a normal website. It sends a short request through the mobile network. USSD is designed for fast, two-way, real-time communication and does not require an internet connection or data to work. (Infobip)

This is different from SMS. An SMS can be stored and delivered later, but a USSD session is live. If your signal drops or you take too long to reply, the session can close.

3. The network routes your request to the correct service

The mobile network routes the request to the relevant system. That system may belong to a network operator, bank, public-service platform, payment provider, subscription service, or another authorised service provider.

This is why the same phone can use different USSD services for different tasks. One code may open a network balance menu, another may open a banking menu, and another may open a subscription or account service. The code itself is only the entry point; the menu behind it is controlled by the provider.

4. A text menu appears on your screen

After the request is processed, a short menu or message appears on your screen. It may show numbered options such as balance checks, bundle purchases, account settings, or help options.

Read the menu carefully before replying. The screen should clearly match the service you intended to use. If you dialled a banking code, the wording should match the bank. If you dialled a mobile-network code, the wording should match the network. If the screen looks unrelated, asks for unexpected details, or shows unclear costs, cancel the session.

5. You reply inside the same live session

If the USSD menu gives you options, you reply by entering the number or text requested. The service then sends the next menu or final response.

This back-and-forth continues until you finish, cancel, or the session expires. Because USSD is live, you usually need to respond quickly. Taking too long can trigger a timeout.

6. The session ends with a result, error, or timeout

A USSD session usually ends in one of four ways:

If the task involved airtime, data, banking, subscriptions, or personal information, check your balance, SMS alerts, provider app, or official account page before retrying.

Important Notes Before You Use the Code

Check network/account status

USSD needs a working cellular connection. It may fail if your phone has no signal, your SIM is inactive, the service is down, the code is not supported on your network, or your account is not eligible for that service.

USSD can work on basic phones and smartphones. Standard Bank, for example, describes cellphone banking, also referred to as USSD banking, as a way to manage finances on a phone without downloading apps; it also says users can use any cellphone as long as the cellphone number is linked to the account. (Standard Bank)

Before using a code, check:

• whether you are using the correct SIM;
• whether your phone has signal;
• whether the code belongs to your network, bank, or provider;
• whether the service still exists;
• whether you need to register first;
• whether your account or cellphone number is eligible.

Verify the code before entering personal details

USSD is often used for sensitive tasks, including banking, airtime purchases, bundle purchases, subscriptions, public-service checks, and account changes. That makes verification important.

Only enter personal details if the code and menu are official. Be especially careful with ID numbers, bank PINs, card details, OTPs, account numbers, and subscription confirmations.

For cellphone banking, Standard Bank warns that users should protect their cellphone, avoid leaving it unattended while signed into cellphone banking, and follow safe banking practices on mobile devices. (Standard Bank)

Stop immediately if a USSD menu:

• asks for an OTP you did not request;
• asks for a full banking password;
• asks you to approve a transaction you did not start;
• shows a provider name you do not recognise;
• hides the cost of a service;
• pushes you into a subscription without clear confirmation;
• came from a forwarded message instead of an official source.

Check costs, fees, and subscription terms

USSD itself may not use mobile data, but that does not mean every USSD service is free. Some provider self-service menus may be free to dial, while purchases, bundles, content services, subscriptions, or premium-rated services may carry charges.

Vodacom, for example, shows some USSD access as free from a Vodacom cellphone for specific prepaid data actions, but this does not mean every USSD transaction on every provider is free. (Vodacom)

In South Africa, ICASA’s regulations on premium-rated services apply to services offered over electronic communications networks, including premium-rated services that may use short codes or related mechanisms. Users should be shown relevant cost and service information before being charged. (ICASA)

Before you continue with any paid or subscription-related USSD menu, confirm:

• the once-off cost;
• the recurring cost, if any;
• whether it is a subscription;
• how to cancel;
• whether airtime will be deducted;
• whether the service belongs to the provider you expected.

Retry safely

If a USSD code fails, do not keep retrying without checking what happened. Repeated attempts can cause confusion, especially where airtime, data purchases, banking, or subscriptions are involved.

Use this safe retry checklist:

1. Check that you typed the code exactly as the official source shows it.
2. Confirm you are using the correct SIM and network.
3. Check your signal.
4. Wait a short while if the network may be busy.
5. Check whether you received an SMS confirmation.
6. Check your balance or account before trying again.
7. Use the provider’s official app, website, branch, ATM, or help page if the issue continues.

For failed, expired, or confusing sessions, use USSD code not working as the next troubleshooting guide.

Escalation route

Escalate through the official provider route when:

• the code repeatedly fails;
• money, airtime, or data was deducted;
• you were subscribed to something unexpectedly;
• a transaction appears twice;
• the menu asked for suspicious information;
• you entered personal details into the wrong service;
• you suspect fraud.

For network services, use the network’s official website, app, store, or support channel. For banking services, use your bank’s official fraud, branch, ATM, app, or website route. For government services, use the relevant department’s official website or verified help channel.

Official support route

Do not treat third-party numbers, screenshots, comments, or copied lists as official support. A USSD code may be real but outdated, or it may work only for a specific provider, product, SIM type, or account.

The safest route is:

1. Start with the official provider page.
2. Check the code, cost, and menu path.
3. Confirm the last-updated or last-verified information where available.
4. Use the official app, website, branch, ATM, or support channel if USSD is not suitable.
5. Avoid entering sensitive information until the provider is clear.

Related Codes and Alternatives

USSD is useful, but it is not always the best option. Choose the route that matches the risk level of the task.

USSD is best for quick, low-data actions. Apps and websites are often better when you need a receipt, a detailed account view, downloadable proof, or a safer login environment.

FAQs

What is how do USSD codes work used for?

This page explains how USSD codes work so users can understand what happens after they dial a code. It helps you know what to expect on-screen, when to continue, when to stop, and how to verify a code before using it.

How does USSD work?

USSD works by opening a live text session between your phone and a network-based service. You dial a short code, the network routes the request, and the service returns a text menu or response. You reply within the same session until the task is completed, cancelled, or timed out.

What is the code for how do USSD codes work?

There is no official code for “how do USSD codes work”. USSD is the technology behind many short-code services. The correct code depends on the provider and task. Use USSD codes South Africa for related codes, but always confirm the latest code with the official provider.

Does this USSD code need airtime or data?

USSD usually does not need mobile data because it runs through the mobile network rather than an internet app. However, some services may still charge airtime, subscription fees, purchase costs, or premium-rated service fees. Check the provider’s official fee information before continuing.

Can USSD work on a basic phone?

Yes. USSD can work on basic phones and smartphones, as long as the phone has a working SIM and cellular network connection. This is one reason USSD is still used for mobile accounts, banking, and public-service access in low-data situations. (GSMA)

Why does a USSD session time out?

A USSD session can time out because it is live. If you take too long to reply, lose signal, move between network areas, or the provider’s system does not respond in time, the session may close. Check whether anything was completed before starting again.

What should I do if the code does not work?

Check the code spelling, signal, SIM, network, and official provider page. If the task involves money, banking, bundles, airtime, data, or subscriptions, check for a confirmation SMS or account change before retrying. Then use USSD code not working for safer troubleshooting.

Are USSD codes safe?

USSD codes can be safe when they are official, current, and used carefully. The main risks are fake codes, copied menu paths, hidden subscription costs, and requests for sensitive information. Cancel the session if the menu looks wrong or asks for details you did not expect.

Are there costs, limits, or eligibility rules for USSD?

Sometimes. Costs, limits, expiry times, and eligibility rules depend on the provider and service. A network balance check may be treated differently from a bundle purchase, bank transaction, subscription, or premium-rated service. Verify the current details with the official provider before publishing or using a code.

Where can I find related USSD codes?

Start with USSD codes South Africa for a broader directory, then verify the exact code on the official provider page. For background, read what is a USSD code. For failures and timeouts, read USSD code not working.