Buy your O2 top up online

Buying O2 top up on Reloadbase is the fast, safe and simple way to stay connected. Stay connected with your loved ones in the UK or abroad with O2 top up online. Whenever you need more call credit or mobile data, you can top up O2 instantly on Reloadbase.

Frequently Asked Questions about O2 Top Up

How to top up my O2 call credit?

When you receive your O2 top up voucher in email, follow the below steps

  1. From your O2 mobile, call the O2 top up number 4444.
  2. From a landline, call 08456 062 277.

In either of these cases, simply follow the instructions.

How can I check my O2 credit balance?

O2 top up voucher will expire after 365 days if you don’t activate it. Once activated, your O2 call credit does not expire as long as your O2 SIM card is active. To keep it active, make at least one chargeable activity like a call, a text or mobile data usage every 6 months. O2 UK will deactivate your SIM card if not active for 6 months.

How long is my O2 call credit valid for?

Check your O2 balance from your O2 number:

  1. Enter *#10# and press the call button. Your O2 pay as you go balance will appear on your screen.
  2. Dial 4444 to hear your balance on your phone.

Check your O2 balance from a different phone or device:

If you have a My O2 account, you can sign in to it from any phone or computer to check your O2 balance. You don’t need your SIM with you.

If you do not have O2 account, insert your O2 SIM into any phone. Turn your Wi-Fi on and go to the My O2 website. There you’ll see your O2 balance without needing to sign in.

How do I top up Three from abroad?

By Call:

  • From your O2 mobile, dial 4445.
  • From another phone, dial 0344 8090222.
  • From abroad, dial +44 7860 980 202.


To chat with an O2 customer service specialist, visit the O2 customer service page and scroll to the bottom.

How do I contact O2 customer service?

There are two options to activate your O2 top up voucher from abroad.

  1. Call 4444 from the mobile phone you want to top up.
  2. Enter *111*# followed by the call button. Then, follow the instructions.