Apple Watch cellular

[Smire]

Hi sorry for silly question I’m advance. 

im with giffgaff at this moment, and just bought Apple Watch from Apple. 
realised about cellular, i was thinking to move to o2 for iPhone and watch. 

im really confused with this. 

can I just buy monthly SIM card- saw £20 for 160gb (24months contract) for phone and watch both? 
do I still have to pay extra for Apple Watch data? Or iPhone and Apple Watch will use data together from 160gb? 

if someone can help me to understand better, that would be really appreciated 

thanks 

[MI5 · Accepted solution]

@Smire 

Yes you can a sim only from O2 to be able to pair the watch but the watch data plan is an extra £5 per month.

https://www.o2.co.uk/termsandconditions/mobile/watch-airtime-plan-terms

https://www.o2.co.uk/help/phones-sims-and-devices?page=device/apple/watch-4/topic/internet-and-data/...

[Smire]

Hi thanks for reply! 

so when I get SIM card delivered, then log in to data plan page on Apple Watch app on iPhone, then I can tick for air time service with £5 extra cost? Am I understood properly? Thanks again. 

[MI5]

@Smire Yes, that's it.