How do I get my phone number from a new SIM?

[Barb123]

Do I keep my old number when I upgrade automatically

[jonsie Level 94: Supreme]

Yes you do @Barb123 

[Budge]

I want to change my sim card as on the new sim card I can get unlimited calls and texts and 15GB of data for £10 a month rather than the bolt on I'm on now as I pay £20 and get unlimited calls and texts and 6GB a month so could save myself £10 a month

[Budge]

(P.s) But want to keep my old mobile number

[Cleoriff Level 92: Chief]

@Budge 

If you are eligible to upgrade then do so via My O2. By upgrading you always keep your number and your billing date is unchanged.