Block Calls and SMS From a Number on Jazz, Zong and Ufone: Codes and Charges

To block calls and SMS from a number at network level, dial *420# on Jazz or Ufone, or dial 420 on Zong. Jazz charges Rs 2 a day including tax, Ufone Rs 2 a day including tax, and Zong Rs 15 plus tax a month. Your phone's own block list does the same job for free, so the paid service only makes sense in a few cases.

A caller who will not stop is exhausting. An ex, a loan agent, a prank caller or a stranger who got your number from a shop. Pakistan's networks sell a service that blocks a number before the call ever reaches your phone. We read the service pages of Jazz, Zong and Ufone on 9 October 2026 to set out the codes, the limits and the charges side by side.

The block codes and charges on each network

Jazz and Ufone both use *420#, and both charge Rs 2 a day including tax. Zong uses 420 and charges Rs 15 plus tax a month, plus Rs 1 plus tax for each call to its menu. Each one keeps charging until you unsubscribe.

Telenor's website refused our requests, so we could not read whether it sells a similar service or what it costs. If you use Telenor, the free phone settings below do the job.

Over a 30 day month, Rs 2 a day comes to about Rs 60 on Jazz and Ufone. Zong's monthly charge is lower, but each call to its 420 menu adds Rs 1 plus tax.

How to block a number on Jazz with *420#

Dial *420# from your Jazz number to subscribe, then choose option 1 to add a number to your blacklist. Jazz says the blacklist turns on automatically when you subscribe this way. Calls and SMS from that number then stop reaching you.

1. Dial *420# from your Jazz SIM.
2. Confirm the subscription. Jazz charges Rs 2 a day, tax included.
3. Dial *420# again and choose option 1 to add a number to the blacklist.
4. To remove a number later, dial *420# and choose option 3.
5. To stop the service and the daily charge, dial *420# and choose option 4.

You can also send "Help" to 420 to get Jazz's list of SMS commands. The service works on prepaid and postpaid Jazz numbers, and it blocks numbers on Jazz and on other networks.

One detail on Jazz's page is easy to miss. If your balance runs out, the service keeps running and Jazz recovers the daily charge later, when you next recharge. So a forgotten subscription keeps building a bill even on an empty SIM.

How Zong and Ufone blocking works

On Zong, dial 420 to reach a voice menu where you block calls, block SMS and manage the list. On Ufone, dial *420# to subscribe and to add or remove numbers. Ufone allows 20 numbers, Zong 50.

Zong's page says its service can also block international numbers at no extra charge, which helps with overseas spam calls. Its menu works in more than one language.

Ufone's terms carry three limits worth knowing:

• Only 20 numbers fit on the blacklist. To add a 21st, you must unblock an old one first.
• Blocking a number stops both its calls and its SMS.
• Ufone says UBlock is unavailable during festive events such as Eid and 14 August.

On all three networks, unsubscribing deletes your blacklist. If you subscribe again, you start with an empty list and have to add every number again.

Your phone can block numbers for free

Android phones and iPhones both have a built-in block list that costs nothing. Open the caller in your call log and tap Block. For most people this is enough, and it saves about Rs 60 a month.

Phone blocking has limits, though. The list lives on that handset, so it does not follow your SIM into a new phone. And on some phones a blocked caller can still leave a voicemail or show up in a filtered list. The settings for silencing unknown callers and spam calls on iPhone or Android go further and mute every number not in your contacts.

Marketing messages are a separate problem with a separate fix. Sending a message to stop spam SMS and marketing calls with 3627 is free and covers all networks.

Block first, then report fraud and threats

Blocking hides a caller from you but does nothing to stop them. If a number is trying to cheat you or threatening you, report it as well. PTA takes fraud number reports on its complaint portal, and threats or blackmail go to the National Cyber Crime Investigation Agency.

Before you block someone who is threatening you, take screenshots of the messages and note the call times. Once the number is blocked, new messages stop arriving and your evidence stops growing. The steps to report a fake call or SMS scam list what PTA asks for.

Watch for one trick. Scammers sometimes call to say your "block service" is expiring and ask for a code sent to your phone. No network asks for that. Never read out a code that arrives by SMS.

And check your balance after a month. A service you forgot about at Rs 2 a day is exactly the kind of quiet deduction that drains a prepaid SIM. The balance save codes for every network help stop other surprise charges too.

Common questions

What is the code to block a number on Jazz?

Dial *420# from your Jazz number. Choose option 1 to add a number to the blacklist, option 3 to delete one, and option 4 to unsubscribe. It costs Rs 2 a day including tax.

How do I block calls on Zong?

Dial 420 and follow the voice menu to block calls, block SMS or manage your list. Zong charges Rs 15 plus tax a month and Rs 1 plus tax for each call to the menu.

How many numbers can I block on Ufone?

Twenty. Ufone says you must unblock an old number before adding a new one once the list is full.

Will the blocked person know I blocked them?

None of the three networks says what the caller hears or sees. We did not test it, so we cannot confirm either way.

Does blocking stop charges if my balance is zero?

No. Jazz says the service keeps running on a zero balance and the charge is taken when you next recharge. Unsubscribe if you no longer need it.

How do I stop the block service?

On Jazz, dial *420# and choose 4, or send DEACT ICS to 420. On Zong or Ufone, send unsub to 420. Your blacklist is deleted when you unsubscribe.

How we verified this

What we checked, where we read it, and what we could not confirm.

Last checked on 9 October 2026. Sources: Jazz's Call and SMS Block Service page and its self-service dial code list, Zong's Call Block page, and Ufone's UBlock page. Ufone's page lists only the prepaid charge. Telenor's website blocked our requests, so its service is not covered. We did not subscribe to any of these services ourselves.