Are 0300 numbers free to call on O2?

No, they’re generally not, but under certain circumstances they practically are. 

On the O2 mobile network 0300 phone numbers are charged at the same standard UK rate as all local 01 and 02 numbers, as well as other national helplines starting with an 03 prefix. However any remaining unexpired free minutes that are on your O2 Pay Monthly or Pay As You Go tariff can be used to phone these numbers for no additional charge. This means that as long you have enough free minutes then calling an 0300 number is effectively free but if you regularly run out of your free minutes then you will be charged on your next phone bill.

Are 0300 numbers “mobile friendly”?

There are two reasons why UK phone numbers which start with 03, including 0300 numbers, are commonly referred to as “mobile friendly”. The main reason is that before July 2015 freephone numbers (0800 & 0808 numbers) were not free to call from mobile phones and were relatively expensive compared to 0300 numbers, this is because the telephone regulator Ofcom had stipulated that calls to 03 numbers should be charged the same as calls to local 01 and 02 numbers. Secondly mobile tariffs often include free inclusive minutes, which can be used to phone 0300 numbers, as part of a monthly contract or a rewards bundle.

However reforms from Ofcom which came into effect on 1st July 2015 mean that 0800 and 0808 freephone numbers are now fully free to call from both landlines and mobiles without even eating into free minutes allowances, which detracts from the appeal of “mobile friendly” 0300 numbers.

Call cost structure

Calling a UK 0300 number from any O2 mobile handset outside of free minutes allowances will cost you a minimum access charge plus a per-minute rate which is defined by O2 themselves.

O2 Pay Monthly customers

All the Pay Monthly contracts currently offered by O2 include a minimum of 500 free minutes which can be used to call numbers starting with 0300, 0333, 0344 and 0345 prefixes, however if you run out of these minutes you will have to pay a per-minute rate of 35p plus a 35p access charge. This means you should keep track of your free minutes to avoid paying these comparatively high charges.

Pay As You Go tariffs

Calling any 03 number from an Pay As You Go mobile with an O2 SIM card will cost you 30p per minute plus a minumum call charge of 30p so please check how much money you have on your balance before you make the call. Alternatively Big Bundle packages are available to Pay As You Go customers which include free minutes that can be used to call 0300 numbers.

Calling 0300 numbers from outside the UK is not free!

Calling 03 numbers such as 0300 helplines from overseas using your O2 mobile handset is not free of charge regardless of whether you have free inclusive minutes remaining on your tariff or not. This applies to both Pay Monthly and Pay As You Go tariffs so unless you have a specialised roaming contract or international “Bolt On” package it is advised that you call such numbers using a landline telephone instead. You should also be aware that you will have to dial +44 300 rather than 0300 to call these UK numbers from abroad and that standard call charges vary depending on which country you are in, therefore it is advisable to confer with O2 customer service representatives before you travel overseas to confirm their international call costs.

Full summary of 0300 call costs from O2 mobile phones

Type of O2 tariffWith free inclusive minutes on tariffWithout free inclusive minutes on tariff
Pay MonthlyFree35p per minute plus 35p access fee
Pay As You GoFree30p per minute plus 30p access fee


Pay Monthly
Pay As You Go