O2 Call Forwarding and Divert

Q: What is the O2 call forwarding code?

To divert all calls, dial **21* followed by the destination number and then #. Cancel it with ##21#. For conditional diverts use **67* when busy, **61* when unanswered and **62* when unreachable, cancelling each with ##67#, ##61# and ##62#.

Q: How do I turn off call forwarding on O2?

Dial ##21# to clear an all-calls divert, or ##002# to remove every divert on the line at once. ##002# is the one to use if you are not certain which diverts are active, since it clears the conditional ones too. There is more detail in our guide to cancelling call forwarding.

Q: How do I forward O2 calls to voicemail?

O2 voicemail answers on 901, and O2 sends unanswered and unreachable calls there by default. If you set your own divert for those conditions it overrides the voicemail divert, so to put things back dial **61*901#.

Q: Can I set up an O2 divert from the My O2 app?

Yes, under My Device > Call settings > Call forwarding. This is the one thing that sets O2 apart from the other networks here: EE states diverts cannot be set remotely at all, so an app route is genuinely useful if you are configuring a divert for someone else.

Updated 7 August 2026

O2 makes it straightforward to set up call forwarding on your mobile. You can use universal GSM star codes, your phone's built-in settings, or the My O2 app. This guide covers all three methods so you can choose whichever is most convenient.

Business call forwarding and diverting setup

Method 1: Star Codes (Quickest)

Open your phone's dialler and enter the appropriate code. These are standard GSM codes rather than O2-specific ones, so they also work on networks that run on O2, such as giffgaff and Tesco Mobile. Note that Lycamobile is no longer one of them — it moved to EE in June 2023.

Divert Type	Activate	Cancel
All calls	`*21[number]#`	`##21#`
When busy	`*67[number]#`	`##67#`
No answer	`*61[number]#`	`##61#`
Unreachable	`*62[number]#`	`##62#`
Cancel all diverts	—	`##002#`

Replace [number] with the full destination number including the leading zero.

Method 2: My O2 App

Download and open the My O2 app (available on iOS and Android).
Sign in with your O2 account credentials.
Navigate to My Device > Call settings.
Select Call forwarding and choose the type of divert you want.
Enter the destination number and confirm.

The My O2 app is particularly useful if you want to manage forwarding remotely — for example, an IT administrator setting up diverts on behalf of a team member.

Method 3: Phone Settings

You can also configure call forwarding through your handset's native settings. See our dedicated guides for iPhone and Android step-by-step instructions.

O2 Call Forwarding Costs

Activating and deactivating call forwarding on O2 is free. However, forwarded calls are charged at your standard O2 call rate. If you have inclusive minutes in your plan, forwarded calls will use those minutes. Once your allowance is used, standard per-minute charges apply.

O2 Voicemail and Call Forwarding

By default, O2 forwards unanswered and unreachable calls to your voicemail (number 901). If you set up your own call forwarding for these conditions, it will override the voicemail divert. To restore voicemail, cancel your custom divert with the relevant code or dial **61*901# to re-enable it.

Tips for O2 Business Customers

If you are on an O2 Business plan, your account administrator can manage call forwarding settings through the O2 Business portal. This is useful for configuring diverts across multiple lines without needing physical access to each handset.

Need advanced call routing for your O2 business mobiles? Connection Technologies can integrate your O2 lines with VoIP systems, hunt groups and intelligent call flows. Contact us to discuss your requirements.

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Frequently Asked Questions

What is the O2 call forwarding code?

To divert all calls, dial **21* followed by the destination number and then #. Cancel it with ##21#. For conditional diverts use **67* when busy, **61* when unanswered and **62* when unreachable, cancelling each with ##67#, ##61# and ##62#.

How do I turn off call forwarding on O2?

Dial ##21# to clear an all-calls divert, or ##002# to remove every divert on the line at once. ##002# is the one to use if you are not certain which diverts are active, since it clears the conditional ones too. There is more detail in our guide to cancelling call forwarding.

How do I forward O2 calls to voicemail?

O2 voicemail answers on 901, and O2 sends unanswered and unreachable calls there by default. If you set your own divert for those conditions it overrides the voicemail divert, so to put things back dial **61*901#.

Does O2 charge for call forwarding?

Activating and cancelling a divert is free. The forwarded call itself is charged at your normal O2 rate for that destination and comes out of your inclusive minutes where they apply, with standard per-minute charges once the allowance is used. Charging is the area where UK networks differ most, so check your own tariff before leaving a busy line diverted long-term.

Can I set up an O2 divert from the My O2 app?

Yes, under My Device > Call settings > Call forwarding. This is the one thing that sets O2 apart from the other networks here: EE states diverts cannot be set remotely at all, so an app route is genuinely useful if you are configuring a divert for someone else.

Do these codes work on giffgaff, Tesco Mobile and other O2-based networks?

The codes are standard GSM rather than O2-specific, so they generally behave the same on networks running on O2. Bear in mind the voicemail number can differ by brand even where the codes match, so check your own before using **61* to divert to it.