To make a call using your Sleek World SIM you’ll need to dial the full international number no matter what country you are calling from, or what country you are calling to. When dialling both locally and international remember to dial the full international format for all numbers.
Step 1. Dial the number you wish to call in full international format. 
For example, to call a Nigerian number press + then enter the country code and drop the zero. You would dial on your World SIM +234803075754 
Step 2. Press the call button. In a few seconds, your phone will ring and you need to answer this call.
Step 3. Your call will be connected. At the end of the call, you will receive a message with the cost of your last call.
Tip!  To make it even easier to dial, make sure you change your favourite contacts into the international format. You’ll be able to dial them using this format when you return to Nigeria so you won’t need to switch the numbers back.
Troubleshooting calls
If you find that you are dialling correctly but still cannot make a call, please manually select a different carrier in your phone Settings. To do this on most phones you can go to Settings > More Network or Carrier > Switch Automatic Off and select another network available.
If you still have difficulty making the call, try replacing the + with a * and adding a # at the end. For example, *234803075754# for the Nigerian number

People calling you on your Sleek World SIM will be charged for a call to the UK. It will vary on the carrier and agreements the person has with their provider. 

If you are experiencing difficulty making calls this may be one of 2 factors.

You may not be dialing correctly or you may be on an unsupported network.

Step 1. You should first check that you are dialing correctly. To call from your Sleek World SIM, you need to call in the full international format. This means you need to call with a + then country code then the number.

If you find that you are dialling correctly but still cannot make a call, try replacing the + with a * and adding a # at the end.

Step 2. Try manually selecting a different carrier: 

On an iPhone:
Step 1. Go to Settings on your iPhone
Step 2. Scroll down to find Carrier
Step 3. Switch 'Automatic' OFF
Step 4. After searching please select a network from the list

On an Android:
Step 1. Go to Settings on your device 
Step 2. Find Wireless and Networks 
Step 3. Then click on Mobile Networks or Network Operators
Step 4. Your device will now search for networks around you
Step 5. Select one of the networks on the list to be connected

Using all other mobiles:
Step 1. On the main Menu of your device, find Settings
Step 2.  Look for the option Mobile Network or Connectivity
Step 3.  Scroll down until you can find the option called Operators or Network Selection
Step 4. Select Manual search 
Step 5. Once search is complete, simply select one of the networks on the list to be connected.
You must always dial the full international number, no matter where you are calling from or where you are calling to:

When calling someone in the same country as you, always dial as though you are calling from outside the country.

How to call Landline (fixed) numbers
  • + (plus sign)
  • Country code
  • Area code (removing the first zero*)
  • Local phone number

Example:  To call this Nigerian landline number from your World SIM:  0480 38000 915 you would dial:  +23 480 38000 915

How to call Mobile numbers
  • + (plus sign)
  • Country code
  • Mobile phone number (removing the leading zero)

Hint:  Save all contacts in the full international format when adding contacts.

*200# for Sleek World SIM customer service

*222# for making free test call

*133# for your Sleek World SIM phone number 

*187# for your account balance 

*121# to access voicemail 

*122# to turn voicemail on 

*123# to turn voicemail off 

*125# to check voicemail settings 

*172# to retrieve data settings

To call you directly from a mobile:

  • enter ‘+’ (plus sign)
  • then your World SIM number starting with 44

Example: from any mobile phone dial: + 44 ### ### ####

Note:  the + sign is recognised by all networks in the world as the universal exit code for mobiles instead of dialling a exit code.

Hint: Generally you will find the '+' sign on either the '0' button, or one of the buttons either side of the '0' button, by holding the 0 down it will convert to a + or press the respective button on your phone.

To call you directly from a landline: 

  • enter International Exit Code
  • then your World SIM number

Example: from an Nigerian landline dial: 011 44 ### ### ####

Hint:  International Exit Codes or International Direct Dialling Codes (IDD) are required to dial internationally out of a country.