Does upgrading sim only require a new SIM card / break in data?

[WFH-Data]

Hi

I have a SIM only (out of contract) of 15Gb for my 4G dongle and want to move to a 50Gb 30 day contract. I have this option on my o2 app as an upgrade path. 

If I take out this upgrade will I risk a period of no data with a SIM card swap or does this upgrade just use the existing SIM and just increase the data allowance?

I'm working from home and cannot have a break in my data. Any advice from people that may have done this upgrade?

[MI5 · Accepted solution]

@WFH-Data 

The tariff will change seamlessly on your current sim card.

[Cleoriff]

@WFH-Data 

If you upgrade the change is immediate. You keep the same number and billing date.

[WFH-Data]

Thanks for the info - I will try this after work & let you know.

[MI5]

I did it myself recently @WFH-Data 

You'll get a text to say your new tariff is active within the hour and your MyO2 will update overnight.

[WFH-Data]

@MI5 All worked prefectly, thanks for your help!

[WFH-Data]

@Cleoriff The cut off date stayed the same and the full alowance has been applied from today (halfway through the billing period). Good advice - many thanks! 

[MI5]

You're welcome