Difference between Upgrade and SIM Only

[PaulThePonderer]

I bought my handset outright and went for an O2 SIM only monthly contract ages ago. Time for me to change tarriff but I'm a little puzzled. 

Am I correct in thinking  ...

if I "upgrade", essentially it's a silent system change for O2 so I don't see anything much apart from a change in the billed amount; contract rolls over seemlessly, number stays the same etc.

if I take out a new SIM only deal, there's an overlap in contract periods (I end up paying twice), new SIM has to be installed, number ported over to the new SIM etc.

[gmarkj]

Pretty much spot on there @PaulThePonderer

[jonsie]

The only change would be to your tariff and there is no crossover period apart from the difference in tariff rate for the month which will be credited or debited to your first bill. Just the one bill

[Cleoriff]

Yes @PaulThePonderer 

That's exactly how it works. If you Upgrade you keep the same sim and number and the change is made to your account.

[PaulThePonderer]

So in my case a new SIM is a way better deal than upgrading.

Does the charge period for the new SIM start from the day you slip it in and start using it, or the date you order it?

[jonsie]

You are better upgrading to sim only

No need to change sim and new deal starts within 24 hours

Only the one bill on the same date as now

[Cleoriff]

No not a new sim @PaulThePonderer 

Upgrade to sim only is the way to go. No contact needed with O2 staff, no sim change needed. As said, it's all changed on the system. We have been doing this for years since we went to sim only and it's effective (and painless Lol)

[PaulThePonderer]

Ok, now I'm confused. I'm already a SIM only customer.

It appears I have two options. One is to upgrade via the myO2 site which offers a very poor choice of options. The other is to buy a new SIM only contract via the shop. 

And the latter involves O2 sending me a new SIM doesn't it? 

[Cleoriff]

@PaulThePonderer 

I am also a sim only customer and looking on my PC they have an option of 100GB data, Unlimited texts and calls for £20 a month.

https://www.o2.co.uk/shop/sim-cards/sim-only-deals#deviceType=phone&contractLength=P12M 

@jonsie  upgraded to this tariff a couple of weeks ago and he, like you and me, was a sim only customer.

[MI5]

@PaulThePonderer All simo deals are available for upgrade https://www.o2.co.uk/shop/sim-cards/sim-only-deals#deviceType=phone&contractLength=P12M